Vancouver is a beautiful city with lots of things to do within a day's travel! There are several companies that offer regular tours to Whistler, Victoria, the city of Vancouver itself, and the North Shore.

Whistler is a year-round destination, with plenty of skiing in winter time and mountain biking, hiking and golfing in the summer. It is a resort town with a pedestrian shopping street and plenty of things to do. Lots of good restaurants and accommodation. It isn't the cheapest, but you get what you pay for. 

Victoria is British Columbia's capital and has an attractive downtown core, including the beautiful Empress Hotel and the parliament buildings. Day trips pick you up in Vancouver, take you to the BC Ferries, and also show you the beautiful Butchart Gardens along the way. You can choose to fly back or even go whale watching. 

The North Shore of Vancouver offers attractions like Grouse Mountain, the Capilano Fish Hatchery, and the Capilano Suspension Bridge. It also offers lots of opportunities to work up a sweat and there are three local ski resorts within easy driving distance from Vancouver. 

For more information, check out Tourism Vancouver's day trips section.

For day tours, check out West Coast Sightseeing or Landsea Tours.

Fly to Salt Spring Island for the afternoon; for information http://gulf-islands-safari.blogspot.com/

Take a 40 minute ferry from Horseshoe Bay for a day exploring the scenic seaside village of Gibsons Landing, or add an overnight getaway to explore the Sunshine Coast. For information http://www.bigpacific.com/

For suggested day trips that are easy to take using public transit check out Tour by Transit - Vancouver BC

For more ideas, this article covers off itineraries around Vancouver, but also goes into day trips from Vancouver further down and is more comprehensive.