For Time-Wasting Tuesday... here's RaidenX. Raiden (wikipedia link) is a classic shoot-them-up game with a top-down view. This is a Flash version of the game that is surprisingly reminiscent of the coin-operated arcade console. Brought to you by googley, this is a tribute to the original.
The game is simple and typical; you fly a plane through waves of enemies and several levels with a boss at the end of the level. You have your main cannon, missles, and a clear-the-screen bomb.
This version is good for about 60 minutes; turn it up and have some fun with it!