I'm sure quite a few people may know about this, but it is worth mentioning again.  When you are looking for a math website to supplement your curriculum, this one is great.  Sorted by great levels and types of math.

If you find one "game" that you think your students should play, just copy the URL of that game into a blog in the Student Community and they can all get the link from there.  Much easier than having them type it in.

Enjoy!

http://nlvm.usu.edu/en/nav/vlibrary.html