LenMiyata took the words right out of my mouth. A hamster ball works wonders! I used to have a hamster I named "Edward Wang Hau Pepileu Tirusky VI" ^_^ and he used to hate it in his cage--all he did was eat and sleep. Not a big wheel fan, my hamster. But you put him a hamster ball and he's all over the place.
I wouldn't get another hamster to keep him company, because most hamsters don't really get along unless they're mating, unlike gerbils. But, they've got all sorts of nifty cages you can buy (or even add-ons for cages) that have tube mazes and all the nifty "hamster toys".
All this hamster talk makes me miss my Ed. Word of advice, don't let your friends hamster-sit for you. He'll die! T_T