During the first TweakWeek popular developers like Ryan Petrich, Dan Zimmerman, Elias Limneos, Grant Paul (chpwn), Filippo Bigarella, Tyler Nettleton, Andrea Oliva, Max Shav and moeseth released over 65 free, open source tweaks.
Petrich is looking for other developers to participate in the project -- which will start "sometime after the iOS 7 jailbreak."
The rules state that developers must release one new tweak everyday for seven days -- and all the work must be done on release day (in one day). All releases must be open source as well.
Additionally, Petrich claims that TweakWeek 2.0 already has over 20 developers, and could last more than 5 months.
Read More via @rpetrich