Open episode guide
Matt posts about his TV Time Capsule idea and this is actually something that I've been wanting to build into junklog. Being able to log and discuss episodes of TV. But I have my own thing someone should build because I don't have time. It would be an open episode guide service with some sort of API. My idea is that it would be like Wikipedia but for episode guide (and movie listings, and so on) data in a structured format. This would make it possible for services like junklog to identify unique episodes and group them. I think there are a ton of tv-based services that could exist if this data were available.
But maintaining a database of that size and keeping it up to date seems virtually impossible for just one guy (me) to do, so some sort of open wiki-style episode guide would do the trick.