I didn't know any one of them, we just meet at the TADHack last week end. Because my team members apologies at the last moment, I joined one of them who forgot his laptop. The third came after five minutes asking "can I join"?
We established a team from three different backgrounds, and started the work. Each one built what he know, and we integrated all of it together.
Luckily, we won.... I enjoyed these weekend...