I like TDs... How about a TD where there are 10 players.
Laid out like this:
There are ten boxes across and ten down, 100 total...
All players start in the bottom of their rows, with basic towers/creeps...
After they accumulate enough kills they move up one....
Each level has better/more towers/creeps...
First to top wins....
You could also throw in a special creep that automatically bumps you one or another back one... Randomly of course...
Wachoo think?