So I’m working on this year’s Geek Gala and have decided to use a carnival theme.
The ballroom we are renting will have 8-10 small booths on either side where our attendees can try their hand at different games for small prizes or raffle tickets.
So far, we’ve got:
2 Fortune tellers
1 Photo Booth
Grand Death Zombie (head-to-head competition using remote control cars to knock over plastic zombie figures)
1 big screen wii style game
I’m looking for low cost games that would be easy to assemble but still be challenging/entertaining for adults. The inclusion of sci fi/fantasy fandoms would be great - like Star Trek, Star Wars, Battlestar Galactica, Dr. Who, etc. Comic book characters and anime also welcome.
You guys are some of the most creative folks I know - so whaddya got?
From the thread title, I thought you wanted to use real chicken-head carnival geeks. You still can.
Easy one to do: Make some little figures that look like “the red guy” from Tron and throw discs at them. Prizes dependent on how many you knock down.
2nd idea: Get a boxing “heavy bag” and make it up to look like Wesley Crusher. No real point to this one, and no prizes awarded, but I know I would cough up a few tickets to smack that snot nose kid around a bit. 
If you’re familiar with the Midwestern game of Cornhole (or “Bags” in Chicago), it is fairly easy to buy or build, and you can paint the board any way you want. The hole could be a wormhole or the gates of Mordor.
Even if you’re not familiar with it, it’s still easy. You take a board of plywood a couple feet on a side, cut a hole in it about four inches across, prop it up at a shallow angle, and try to toss beanbags into it from 20 or 30 feet away. I think the game is probably pretty universal; it’s just the name “cornhole” that’s distinctively Midwestern.