Love this! Preschool here, but easily adapted to elementary classroom.
Lego Tables and Graphs
Playhouse in a hallway! I'm going to use this idea and adapt it to create a tent in front of the library for Summer Camp Read! Just using long tension poles, sewing pockets on the back of the green fabric for the rods, then opening the front of the "tent" and rolling it back to enter the library. Cool! I also bought astro turf for grass...
Using tension rods to make a tent, puppet theatre, etc.
Build an exploding chain reaction with craft sticks. This is so awesome! Video in the post.