Example projects that I like

http://classblogmeister.com/blog.php?blogger_id=162321
Third-grade teacher's class blog, with PictureTrail stuff.

http://mrkelln.wordpress.com/
A middle school teacher writes TO and about his classes. He's experimenting with incorporating lots of new technology (Moodle for science lessons, Voicethread, etc.) in ways that the students learn the technology and use it themselves for projects. I like the informal tone of his posts to his students -- "you guys", etc. Interesting and kind of inspiring site.

http://msgee.edublogs.org/
An interesting example of using a class blog to motivate students. The teacher posted about reading strategies she was teaching, and her third-graders posted about their implementation of those strategies.

http://math8geometry.wikispaces.com/
Eighth-graders each made one page of a geometry wiki. Each page teaches one concept well. Interesting, and I bet the kids enjoyed doing it, but I bet they learned more about making a wiki page than about geometry overall from this project. Fun and a good way to learn technology, but not necessarily an efficient way to learn the geometry itself.