I still have one, but it's been years since I used it. I have no idea if it or the games still work.
Probably the only places you can buy them these days are online sites like eBay.
I don't remember too many of the games... Pac-Man was good, of course. Pitfall, River Raid, Spider-Man, Super-Man... those were all pretty fun. I've forgotten a lot more than I remember, of course.