If you haven't played "World of Goo" - you should.

This goes for EVERYONE: World of Goo is one of the best puzzle games I've ever played.

It's appropriate for all ages, is hilariously funny and best of all, it's one of the smartest games I've played since Tetris - and that's saying a lot, as I play Tetris every single day, and have since I was 9. It's available on Mac, Windows and WiiWare, so there's a greater than 90% chance that - if you're reading this - you can actually play it. It's only 20 bucks and is completely DRM-free (and like all games, I know a certain subset will pirate, but in this case, it's an independent developer and I'd love to see you guys reward their hard work with a little dough).