Need help with a school project:(

Hey everyone, I’m new to programming in Action Script, though I’ve messed around a bit in Java and Visual Basic. For our class we’ve been assigned to make a flash game in groups, and our group has decided they want to do a base defense game. I’ve been looking hard for open source/tutorial versions of a simple base defense game, but all I’ve found are tower defense games. Can anyone help me out with a link to an open source AS3 base defense game? I’d really appreciate the help.
Thanks!
Archon