The original interactive cat toy - the Da Bird comes highly recommended.

Got an overweight cat? Da Bird is one of the best cat toys to stimulate your cat to do some exercise!  As you swing your rod, the attachment spins overhead and the bird-like motion will get any cat's attention. It will drive your cat crazy!!  Make sure you put away this toy when not in use as through experience, I have realised that the cat loves it so much that he will dig it out himself and play with it.  But no worries, because if your cat does destroy the toy - there are replacement lures available. 

There are also other types of amazing interactive cat toys made by Go Cat that will make your cat go crazy!!