I just have to agree that creating a 3D model of a cell is a great idea and have been working on other types of building assignments along those same lines. If anyone remembers the Edible Cell Contest lesson plan from years back, it's just another great way for students to really internalize the various parts of a cell.

Being an art teacher by degree, but working in Instructional Technology, I created a sandbox in SL for a team of teachers who wanted to explore the possibilities. I created a two-fold art lesson and put the lessons on notecards which were then put into a small box in the sandbox. The students would read the hover text that says Get Assignments and when they touch the box, the notecards would be vended to them. One was an art analysis of Sunday Afternoon on the Isle of La Grande Jatte, and the other was a collaborative (small group or partner) building assignment where the students would have to create a 3D model of a color wheel. This would require many social and spatial skills.

I think another great assignment would be for students to create math manipulatives that they could use to demonstrate to younger students who were not inworld but would get a kick out of seeing avatars pushing around huge cubes that they knew stood for 100.

I have a short video showing the sandbox at

http://www.teachertube.com/uvideos.php?UID=12508