TweakWeek is a project mainly written in Objective-C, it's free.
open source tweaks; part of http://www.tweakweek.com
My contribution to Tweakweek!
Open-Souced Projects!
Do whatever you want with these besides selling it commercially :p
Day-1; launchSound
Day-2; UShare
Day-3; MailKeyboardHide
Day-4; FunnyCaller
Day-5; QuickMath
Day-6; ToDoNotes
http://www.youtube.com/watch?v=ny6wXf-3XlM "Demo Video"
Day-7; HiddenCalllogs
Okay, it's finally over!