Teams of autonomous robots and fortress elements attempt to knock each other out by scoring 5 hits on a set of 8 photoresistors per robot or fortress. Once a photoresistor has been hit, it cannot be hit again. There's a very restrictive budget limit for each robot to keep the competition accessible to the most teams. The first team to knock out all the opposing robots (but not necessarily fortresses) wins. A draft set of rules is attached as a text document.
This is a proposed parts list, but certainly not the only way to construct a robot, and not one that has been prototyped yet.
Parts list: (total cost per robot < $80)
Tamiya #70108 Tracked Vehicle Chassis: Amazon $16.59
Tamiya #70168 Double Gear Box: Amazon $11.84
Arduino Uno R3: Amazon $23.01
20pc GL5528 photoresistor: eBay $1.74
LED 100-pack: eBay $2.57
2.1x5.5mm DC plug to 9v battery clip: Amazon 2/$2.83
2@ 28BYJ-48 5V 4-phase 5-wire stepper motor w/ ULN2003 driver: Amazon $3.50
SainSmart HC-SR04 Ping sensor: Amazon $6.61
74HC595 8 bit Shift Register DIP 16 50pk: eBay $8.77
CD4051BE Analog Multiplexer 8:1: Jameco $0.45 eBay 5/$1.50
1K resistors 100pk: eBay $2.50
Laser pointer: $1-$10
(note: must be able to replace the manual switch with a controller based trigger)
Once the method for identifying teams has been established, a microphone, speaker, and switch will probably add about $15 to the cost.
Will be added once a prototype has been built.