Hi,
challenges would be really nice, it's been discussed before and from what I recall, several things are sort of getting in the way.
1: there is no trial version of playmaker which makes it hard to attract people with such challenges
2: what kind of gain would the winner gets, since he would have to have playmaker already, this is tricky, maybe team with an asset store provider and have him to offer for free an asset for the winner
3: Who would decide who's winning, since it's very subjective, some kind of challenge board, system and rule would need to be defined.
Bye,
Jean