Article accessed through BSU library that discusses benefits of PBL, relationship to standardized testing, and how it can be differentiated among other themes.
This article was written in 2006 and looks at elementary students doing PBL and how it affected the teachers and students. Seems still very applicable.
Another option, similar to Popplet that can work as an online visual bulletin board for students to gather inspiration from. Pintrest might work better as they can add to their own board and also search within other people's pin boards to pull ideas from.