If you're already making plans to attend this year's php|tek conference (2009) then Matthew Turland has a question for you:
Think you might like for a Hackathon to be included in the Unconference? (Or want to know more about what such an event would entail?)
If you'd like to get in on the discussion, there's already a Google group set up that you can join to keep up with the latest. The group just started up , so there's not a whole lot of content there yet so go over any voice your opinion on the matter. Oh, and if you're looking for a quick and easy URL that'll get you there, use http://tinyurl.com/tek09hackathon.