I always wanted to get into the Ape Quest RPG, back in the era of episodic games. I'm not sure what they actually did with the gameplay (I had dreams of it being a very experimental Super Mario RPG-type game with original Ape mechanics in each chapter, but I think it was a lot tamer than that,) but I always an interested in giving a Piposaru a try.
There was also an unusual Ape racing game for PSP, it had a play mechanic where the apes had wheels in their paws and could switch between standing high or spread low.... But it looked really slow and I have a feeling it sucked.
Oh well, at least there was the pants-vaccuming game to try.