Gotta love those freebies!  If you haven't seen this website, you're missing out!  Be sure to check out each topic because there are cross-over items.  For instance, a first lunar landing model in the "kids" area.  The "science" category really has some neat projects. 

These are great "let 'em whirl" projects! 

I recommend printing them out on 80lb paper.  Have fun!  We are!