OK, so Google doesn't support Wave anymore, but it did start a Google Labs project with the remnants. Google Shared Spaces offers a way to create small, intimate spaces to share with others. Simply create the space, send out the URL, and in no time you have a space to collaborate with other users. In your classroom, you and/or your students can collaborate on a Yes/No/Maybe gadget, a shared map or drawing, or a mind map. Spaces is still very young, and I expect to see more uses soon.