I'm sure you've seen the films and the TV programmes about Robin Hood and Sherwood Forest. If you've never been, Sherwood is just south of Sheffield near Worksop.
I took my kids this weekend and we had a great time. When we arrived there was no sign that anything different was happening until we go to the Major Oak, which is the tree which it is thought that Robin lived in.
When we go to the Oak we saw a demonstration of medieval sword fighting, had to hand combat and fighting with bow staff's. We tried archery and then we all had a go with the swords and the armour. The day was actually better because it wasn't really advertised. I'd definitely recommend it if you are Sherwood way.