University Parks, Oxford
Not so many tourists visit Worcester but it's one of the nicest colleges, and is the only college with a lake. It's at the western end off Beaumont Street, near to Walton Street and Jericho.
The University Parks is a nice place to walk, picnic or just escape from it all. It's also the home of University Cricket Club and in summer you can play football, frisbee, tennis, etc.