I second small rubber balls, especially if you have a hallway of some sort. My cat loves bouncy balls, to the point that he'll start panting and we'll have to put them away otherwise he'll just keep playing. We'll each stand at one end of the hallway and throw it back and forth. He likes both chasing it when it's rolled on the floor and leaping in the air when it bounces. Sometimes if there is just one of us or if he's bored and we're busy, he'll even play fetch!
Also if you cat likes catnip I highly recommend Yeowww brand. My cat went crazy just at the box before it was even open! He loves the banana and rainbow (though I did have to reinforce the stitching in the arches a bit). As another way to play is to take a small box (shoe box works well) and put it over a toy (both the capnip toys and bouncy ball work well for us). Our cat will keep pouncing and pushing it around with his nose until he finally gets the toy.