Red vs Blue
Red vs Blue with humans and aliens working together?
Intresting.
Lets stretch that idea a bit though into making it a reality (As Lava always loves to do

). First, you'll have to either:
1) Make each player model red and each model blue then code the damn thing to get it to work.
or
2) Use some sort of client/Qvm/server-side/whatever command to 'tint' the models blue (If, of course that function exists in the game, if not, it'll have to be #1).
And what about the buildings? They'll have to be colored too (Back to painting them again) and then after all of that, code it so there'll be Blue vs Red teams with Humans/Aliens as sub-categories.
What about spawning? Does the egg become the main 'spawner', or does the node? One interesting idea is that You could be either human/alien in a team,
IF you have the proper spawn for that team (Either telenode or egg). If not, you'll have to choose the race that does have their proper spawn and thier proper Rec/Om.
I could keep going on, but I'm saying all of this because your interesting idea just needs some reality checks to make sure to see how easy it'll be to do something like this. Now, I don't know why I'm up this late talking about this. I'll rabble on tomorrow, cheers!