Sorry about the new-ness of this idea: that's almost certainly my
fault for not being quite sure how to engage folks.  I've been working
with WMF folks directly on this project.

The upcoming hackathons are mostly hackathons in particular places,
AIUI: New Orleans, India, etc.  The goal of this challenge is to
provide opportunities to basically anyone who can take a weekend or
two to hack some code.

It's basically an experiment.  If we run banners for a week and
challenge the entire Wikipedia community to spend a couple of weekends
hacking, what results might we get?  Not sure how well it will work,
but we're certainly going to give it a try.