Sort of off-topic, but this thread reminded me of a gametype I loved in Warcraft 3, where you would draft units from different pools and ultimately fight each other round-robin style with the units you drafted. Man... Warcraft 3 customs were the best. People nostalgia on Halo customs, but Warcraft 3 customs spawned complete genres - Tower Defense, DoTA, and probably some others that aren't coming to mind right now.