An idea I'd like to see: Editor Wars, the game of hacking at code.
Hackers compete on how fast they can complete code editing tasks from a variety of languages, with results plotted and dissected on a web leaderboard. The idea is not to evaluate language understanding or design, but simply editing skill and speed in the kind of thing that editor flame wars start over.
The tasks could be simple refactorings, like renaming a function throughout a source tree, or extracting code into a method. I'd expect this would show advantages of specialized refactoring tools in some IDEs. Other tasks might be more complex, like writing a new set of functions, a whole class, or adding functions to a class to conform to a protocol or interface. Good template support and autocomplete might be an advantage here. Or maybe you want to add conditional debug logging around a set of functions, with each call having a separate hardcoded counter value? Surely powerful macros win this task? Naturally, new tasks could be submitted by the public, and voted on. Each task would have a "correct" answer, but if you're really clever you could always suggest a better correct answer.
Use of extensions and custom macros would be happily encouraged, as long as you can share what you've used.
You'd need either an editor plugin or at least something that watches files efficiently to get the split-second timing your contestants will demand. Ideally you'd be able to record keystrokes and grab the source for any macros you call, then the site would be able to show a replay for the viewing public.
It'd be fascinating to learn how other people use your favorite editor by watching the best of the best compete. Not to mention, just imagine the forum threads arguing over the graphs from the vast database of editor timings.
Anyone want to build this?