Recommend some PS3 Games

My girl just got a PS3 for her new HDTV and now we need some games to play. I have been searching around but haven't had much luck on finding something that fits the type of game she enjoys playing.

Basically looking for a cartoony, arcade style game, that is easy to pick up and play for an hour, and easy to learn. Co-op would be a great addition to that check list. Are there any Mario-esque games available for PS3?

Any recommendations would be great. For reference, she enjoyed Castle Crashers on xbox.

Thanks!

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