It's apparent that people like the flexibility of being able to play any time. I think for the first tournament it will boil down to something like this:
- there will be a special page (probably a really crappy looking page, at the beginning)
- there will be a list of people that are a) online and b) in the tournament that you can challenge
- challenges pop up as a notification when you're in the lobby or tournament page
- tournament winners will be based on the leaders through elo ranking
- every game you play also gives you one additional chance in a lottery that is done at the end of the tournament
The tournament would run over three days, probably Friday to Sunday or somesuch.