Rochester is conveniently located for many fun day trips. The first and most popular is probably Niagara Falls. In about 1 1/2 hours, you can be experiencing one of the wonders of the world. Whether you decide to cross into Canada or stay on the US side, you will not regret the trip to the falls.
Another great idea for a day trip from Rochester is a wine tour along one of the Finger Lakes. Wineries dot the shores of Keuka, Seneca, and Cayuga lakes and they are producers of some excellent wines. The area is especially known for it's Reislings. Many local limo companies offer tours so that you can enjoy the area safely. There are also many great bed and breakfasts if you want to make it an overnight.
Letchworth State Park is also a short drive from Rochester and is beautiful in any season, but particularly in the fall. It has the nickname "Grand Canyon of East" which is well deserved. Here you can enjoy a great variety of activity including hiking, biking, cross country skiing, and more. You can even take a hot air balloon ride and see the scenery from the air.