There is a game on the app store called "Where's My Water" that is really fun and uses fluid dynamics in its gameplay. You can check out a video of the gameplay... You use your finger to remove dirt from the screen, and then the water just flows to the new area.

Anyone knows what engine this was made in and how they where able to get the fluid dynamics in there? I'm using the Corona SDK for mobile development and want to do something similar like this (a game with fluid dynamics).