For those who feel that thumb wars aren't violent enough, I give you Omnibot Battroborg Thumb War Fighting Robots.
Putting a modern spin on a traditional game, Battroborg Thumb War Fighting Robots work by locking the base of the robots together and each player trying to "knock out" their opponent by hitting the enemy robot in a particular place that will cause the robots torso to fly out. Both robots are not created equal, however; the blue robot is an expert at jabs while the red robot has a mean uppercut. In addition to attacking, the robots can also block each other, making for complex and interesting bouts.
A cross between traditional thumb wrestling and 'Rock'em Sock'em Robots, Omnibot Battroborg Thumb War Fighting Robots will take your thumb wars to the next level.