I'd like to see a timed competition, whereby mappers create the best map - regardless of size or quality - in a week. This, I heard was done in 24 hours with the best CS:S mappers, and it really worked, so a week could give ample time to make a small decent map.
A template competition is another idea I had, and has been mentioned before, although I think the template should n ot be restrictive such that all the maps are similar, but so that ey items such as spawns, CPs etc. are in the same place whilst the layout can be radically different.
It would also be interesting to have a balancing contest, all mappers start with the same map template, and then have a certain amount of time to balance the map. Whichever map plays the best on a specially organised gameday wins.
So, thoughts?