Idea: site to match hackers with short-term one-off gigs
Sites like Craigslist, Rentacoder and Elance are flooded with posts offering unreasonably low pay, as well as responses from offshore sweatshops that produce exceedingly bad code[0]. Posters have taken to hiding "put foo in the subject so I don't have to read spam" on Craigslist due to the overwhelming response to ANY ad. I think there might be room for something a little more exclusive.
My initial concept for this is that hackers would be screened for membership. It wouldn't be a high bar - a link to a HN account associated with a few sensible comments, a blog, a github account or similar would be enough to establish credibility. The site would also be policed a little more as far as postings go. One idea is to use a flagging system that can cause posts to be moved, and to have sections like "work for equity" and "work for pay".
[0] An example from an actual project I fixed after it was initially created by such a sweatshop can be seen here: http://paste.lisp.org/display/76132