I have a friend coming over, and she has a 3 year old son, what should I do that can entertain him too?

What sorts of things are 3 year old kids into to? I don’t have any sort of toys around for him to play with, I have two cats, who I’m sure will hate him. Any ideas? I have a game system, Sega Dreamcast, and maybe a few movies he might like, like superman, spiderman, etc.