Two things I'm interested in are games, and psychophysics. Given that cognitive experiments are basically games anyway (albeit, really boring ones) can we have a game that is essentially a perceptual task? After trying to program Tetris, I thought about more games and remembered Missle Command, where you have to make bearing judgements ... Long story short, here's a demo of a modified Missle Command game/task.
Many possibilities for 'attentional' manipulations here. What if a target appears from an unexpected location? What if the speed was varied and had a distribution. What if there was a probable angle for hitting the target for each of those 'cannons'?