As far as video games go, it doesn't get much simpler than Pong -- two paddles, one ball, no complications. A classic, to be sure, but definitely not the flashiest game when pitted against the average smartphone title -- maybe that's why Atari is asking indie developers to jazz it up. Yes, the Pong Indie Developer Challenge is in full swing, and Atari has pared down some 90-odd submissions to mere 15. Not familiar with the contest? Here's a quick refresh: Atari is looking for indie developers to re-imagine Pong for iOS as a fun, original, visually interesting and overtly marketable title. The stakes? Winners can score up to $100,000 and a publishing contract with Atari. Many of the semi-finalists' redesigns are as simple as adding multitouch gestures or bending the traditionally square playing field into a more circular court, but a few ambitious developers mixed it up with 3D playing fields, anthropomorphic paddles or augmented reality multiplayer. Check out Mashable's collection of contestant trailers at the link below for a look at the Pong of tomorrow. As for us? We're still pretty pleased with yesterday's model.