I mostly play solitaire and Tower Defense flash games but recently I wanted to give my kids some less violent video game alternatives so for the PS3 I got them Flowers, Critter Crunch, and Little Big Planet.
Flowers and Critter Crunch you can buy online and then download. Flowers is a very cool game where you are a flower petal and you fly around using the PS3 motion detector and transform kinda dead areas into green, flowery areas. It is fun and different.
Critter crunch is an amusing, fast paced puzzle game and it's only $6 to download.
Little Big Planet is a game where the players can design their own puppet person and then run and jump around and get points, bonuses, and new puppet clothes. You can also create your own maps. My kids like it and I think they will play it for a while.