Cambridge!
With 32 colleges and 50 departments you can't move far in Cambridge without seeing the university which dates from 1209. Many colleges can be visited (except during exam time) and apart from the popular ones this is free.
Of the 587 Nobel laureates worldwide 120 are associated with Cambridge university.
There are (about) 18 museums in Cambridge, many associated with the university, so just about any interest is represented.
With several venues for live shows and two multi-screen cinemas there is no lack of entertainment.
There are countless pubs, cafes and restaurants - too many to list but you will not go hungry or thirsty. Maybe try the The Eagle dating from 1666, which is where Watson and Crick anounced they had "discovered the secret of life" - DNA.
If you have young children with you there are numerous (free) public swing parks including one with a large paddling pool. For more excitement try one of the 'soft play' areas in or near Cambridge.

Check out some of the picturesque villages nearby, starting with Grantchester just 3 miles upstream from Cambridge.

Within about half an hour's drive you can reach:
- Angelsey abbey (National Trust)
- Wimpole estate including kids' farm (National Trust)
- Ickworth manor (Nation Trust)
- The Imperial War Museum at Duxford with planes from Spitfires to B52 and Concord
- Shepreth wildlife park - great for kids

Within an hour's drive you can reach
- Bletchley park, home of the code breakers and the first digital computer
- Milton Keynes for a touch of indoor skiing of indoors skydiving
- London on the train.

Oh dear, this list is getting too long. Just come and find out what a great place this is to visit.