http://eduscapes.com/tap/
Here are some PBL resources:
Project Examples to Convert to PBL:
1. http://www.schools.utah.gov/curr/science/sciber00/8th/machines/sciber/rube.htm
2. http://www.mousetrapcontraptions.com/tips-9.html
3.http://en.wikipedia.org/wiki/Rube_Goldberg_machine