A favourite website of ours is the freeware-tastic
Shmup-dev, a community of people who like to develop (or even just play) quaint, old-fashioned 2D shoot-em-up games.
Being vigorous, competitive sorts, they've announced their third 2D shooter competition, called the Autofire 2007 Shooter Competition.
Go here to see the rules, which include a size no greater than 20Mb, a January 1 deadline and a stipulation that the game must have an autofire feature of some sort.
We're happy to admit that we won't be entering but, like the sideline-sitting, consumerist gluttons that we are, are rather looking forward to the entries becoming available for download.