Chibi Robo was a game I picked up on a whim a long, long time ago. It wasn't really advertised, I didn't really know a lot about it, but it looked kind of cute, so when I found it in a discount bin I decided to give it a shot. I'm so glad I did.
In brief, Chibi Robo is a platformer/adventure game where you play as a small home-cleaning robot that has just been purchased by a family. Your job is to slowly work on cleaning their home, while being careful not to run out of batteries (a game over, equivalent to dying), battle small dust-bunny like creatures, and make the family's life better. Interestingly, this does not always involve just cleaning the house; as you progress through the game, you will meet characters beyond the main family members, such as toys and pets, who will want you to do favors for them. Fulfilling favors for the family members and toys will raise the happiness level of the house, allowing you to go to new areas and receive new gadgets (the chibi-copter that popped out of my head and let me fly around the room was definitely my fave). Sometimes figuring out exactly where to get what a certain character wanted was a bit difficult, but I really enjoyed when I finished the requests and got my new area/item to play around in.
There are more Chibi Robo games available in Japan (mostly for the DS) than there are in America, but both countries got the recently released downloadable Chibi Robo E-Shop game, although it's more of a photo taking game than anything else. Chibi Robo for the GameCube is the first one in the series, and is one of the best as well. Fans of Harvest Moon or any other simulation type games will really enjoy Chibi Robo, as well as anyone who likes to play 'cute' things with a good story.... and of course OCD people (it is a game where you clean, after all). If you're looking for a nice game to sit back with, relax, and enjoy the simple sweetness of life, you should give it a try.