There are plenty of things to see and do within London beyond the usual tourist sites.   

Sporting Activities: Just because you’re in the city, your golf swing doesn’t have to suffer. Urban Golf has come to London thanks to a state-of-the-art facility in Soho where you can play over 50 of the most famous courses with the latest in golf simulators. Who knew that you could play Pebble Beach while smack in the middle of an urban jungle like London?

If you really want to experience life like a native, take in an afternoon, or evening, at the dog track. Sure, it’s not the same as looking at famous pieces of art or snapping photographs of imposing architecture, but sometimes it’s the everyday sort of activities that really make a trip stand out because you’re behaving like a local. The easiest location to get to is probably the Wimbledon Greyhound Stadium for all your betting needs.

Or spend a Sunday afternoon at Ham Polo Club in Richmond on Thames. Take a picnic or buy from the "Chukka Tucker", and watch the fastest stick-and-ball game in the world.  Just 12 miles from the central post office, you will feel like you are in depths of the country.

Winter: Insiders also point to ice skating at Somerset House, centrally located, as a fun way to spend a few hours during the dreary winter months. From the end of November through January, the courtyard at Somerset turns into a winter wonderland. If you think skating is for wimps, then the outdoor ice climbing might be just the bit of adventure you’re seeking. This winter Somerset House adds an 8-metre solid wall of ice for thrill-seekers to try their hand at this sport without any real danger.

Walking & Exploring:  One of the best ways to see the more unique parts of London is via a walking tour. There are many companies offering many types of walking tours covering everything from pubs to ghosts to architecture to Jack the Ripper. You is advised to check if the guides are registered with the London Tourist Board. If they are, they will proudly wear the "Blue Badge" which is an indication they have passed rigorous tests on their knowledge of London. Most walking tours take between two and three hours and run both day and night. The company with probably the largest inventory of tours is " Original London Walks " but there are many others.  If you own an iPod or MP3 player then you may be able to find downloadable guided walks of London.  The great thing about these walks is that you do not need to reserve ahead of time.  Just show up at the appointed time and location, pay the small fee, and enjoy the walk.  The Original London Walks will even do custom tours for you.  There are many places you can visit on your own without tour guides also. The number 11 guide has an expanding section on bus trips to places off the usual tourist routes ieg walks in Lincolns Inn and Regents Canal.. Another good option is "Mosaic Walking Tours" - slightly idiosyncratic but with real insight into "London behind the scenes" - the link goes to their "Sights and Symbols of London" tour but they have a few others. You'll need to book, as groups are kept to a manageable size; all are equipped with radio headphones so there is no need to huddle around the guide. Even this (former) Londoner, found a lot that was new with a lot of information delivered in an entertaining manner by an extremely well-informed guide.

Boroughs:  London is divided into Borough - essentially Governmental districts - as well as the City of London (the 'square mile').  The Boroughs are generally thought of as 'inner London Boroughs' and 'Outer London Boroughs'.  Westminster, Southwark, Lambeth and Kensington & Chelsea are four of the 'inner' Boroughs where visitors to London generally spend most of their time.  One way to find things to do 'Off the Beaten Path' is to go outside these Boroughs, or to look beyond the top tourist destinations within them.  Each Borough has its own Council webpage that generally lists all the activities, museums, parks and attractions within their Borough.

Specific Borough Ideas:

Greenwich:  This is where time begins, is an area of London set on the Thames just below Canary Wharf and is well worth the time (doesn’t take long) and effort (not a lot required) it takes to get here.

You can catch a City Cruise boat from Westminster and Tower piers - it takes about an hour to reach Greenwich. A plus is the commentary by the boat crew as you float gently down the Thames (and at the end you are "encouraged" to give a donation). The trip costs around £16 for an adult return. You can also get a cheaper (cheaper still with a Travelcard) Thames Clipper boat from various piers on the Thames (such as Embankment and Tower Hill) and these boats whisk you quickly past Canary Wharf and drop you off at Masthouse Terrace, from where it's a short walk along the water front and then through the foot tunnel before you emerge at the other end right next to the Cutty Sark and the City Cruise terminal.

There is so much to do in Greenwich that you can easily spend a day or more exploring the local environs.

To start you can take a look at the Cutty Sark , the last of the great tea clippers. She used to ply the tea route to China (with other famous ships such as Thermopylae) before ending her days transporting wool from Australia, where she famously overtook the steamer the Britannia, before being sold to the Portuguese and being renamed the Ferreira.

After leaving the Cutty Sark walk up the street before turning right and then heading in to Greenwich Market, which has held a royal charter since the 17th century. The market changes with the days so best to check before you head down just in case you arrive at the antique market when you are looking for coffee beans or "designer" teas.

From there head down to the Old Royal Naval College which is now the home of Trinity Music college (part of Greenwich University). Originally King James I built a palace here (including The Queens House for his consort, Anne of Denmark). Then in 1694 by Royal Charter Greenwich Hospital was established to offer a place of respite for Naval Pensioners. Most famously of all the buildings were designed by Sir Christopher Wren (as of  St Paul’s cathedral) and the Painted Hall and the Chapel remain some of the most beautiful buildings designed by Wren (rivaling even St Paul’s in their own way).

When the Painted Hall was completed it was originally intended to be the dinning hall for the pensioners. However once the building was ready for use it was decided that it was far too nice a place to have the mostly  drunken old sailors cavorting around...and they were promptly moved on. Perhaps the painted halls most esteemed visitor of all was Nelson, who didn’t actually get to enjoy the building as he was here as part of his funeral after the Battle of Trafalgar.

Its also worth visiting the Chapel on the first Sunday of each month as Trinity College holds various music recitals at 3pm.

Once you have had your fill of old buildings pop across the road (WAIT though, the road is very busy on the weekends) and visit the Queen's House, as mentioned above, and even better still the National Maritime Museum ( free to enter, like all National Museums ) which houses an excellent collection of bits and pieces associated with, funnily enough, the sea. The museum even has Nelson's uniform he was wearing when be bought it fighting for Blighty, King and Country and everything good at Trafalgar.  And yes, you can still make out his blood on the uniform. Check the website for the current exhibition.

The museum backs on to Greenwich Park, a short walk from the  Royal Observatory where the term "Keep your eye on the ball" comes from. The observatory contains an excellent collection of items related to its history and even has some of the original Harrison clocks on display.

At night a laser extends out along the Prime Meridian and its surprising how many older "prime meridians" there are at Greenwich (each astronomer had his own meridian that he worked off). Unfortunately for the astronomers when the main observation building was built the windows were a couple degrees out of alignment, so this meant all the work carried out by the astronomers had to be done outside in the cold.  

After finishing here it’s a short walk back to Greenwich where you can get a bite to eat. There is an excellent chain bookshop called Ottakers which is well worth a visit if you want to take something up to the park to read on a sunny day. Once done you can get back on a City Cruise boat and head back to Westminster or jump on the DLR and head back towards Bank or Tower Hill. Or, for a different experience, walk under the Thames through the 1902 foot tunnel for a view of Greenwich and the beautiful Maritime Museum buildings from the other side; takes only 10-15 minutes to walk through and get on the DLR train at Island Gardens station on the other side.

For Students:  If you’re a student looking for a good time on the cheap, check out London’s many universities or university colleges. As everyone knows, students are notoriously cheap and chronically strapped for cash and helpfully all colleges and universities have a students' union. Usually there’s some sort of chill café and most definitely a pub and club area. Within the confines of the students' union, students (and those who still wish they were students) will discover a land of cheap draught beers, 80s-themed dance nights and live music. Of course, there is a catch. Not everyone is always allowed in. At some universities, only actual students of the school (and sometimes their guests) are allowed to use the facilities. At other schools, you might have to just pay a couple pounds extra at the door in order to get in on the club nights. Either way, it’s worth a look because if you can get it, it’s bound to be a good time without breaking the bank.

 Plenty of further ideas available at  Olympian