Pop in to Norwich Castle for a £1

Norwich castle does a great offer where if you visit in the last hour before closing, you get in for a quid. Which is good, as the normal adult admission price is currently £6.60. While it is a bit of a push to see all the exhibitions in an hour, you can always come again, and it is a nice afternoon activity when you are looking for something out of the ordinary to do.  
Walking around you find out about the castle keep, how it used to be a prison,  and you can don various ridiculous outfits. There are plenty of exhibitions, from Boudica, to Egyptian, Anglo-saxon and Viking; there is even a section on the wildlife in the Norfolk broads. While some of the exhibitions seem quite random and a little out of place, the building is impressive, and it is an interesting way to spend an hour, especially as it only costs a pound!