I don't read too many blogs, so I was not aware of the challenge. The big question I have, is how should a 48 hour game be different from a 24 hour one? It will be interesting to see the results.
One concept I'd like to see is a 24 man-hour game. Unlike the normal contest, you're allowed the help of your friends, but the time is divided between the number of people present. Four people yields a game in six hours, for instance. Most companies are not one man affairs, after all, and it would be an interesting experiment to see how well work can be delegated. (Too many cooks spoil the game?)
Some time ago, I ran across some games from the reverse engineer contest, which looked like fun if we can ever stage it again. (Make a character sheet, trade, and then make an entire game based on that one document!)
Nice find there, Dyson. I like the Concept but there is something more daring, snappy and devilish about a 24 hour one. In 48 hours, you might get some sleep or something. In 24 hours, you can forego sleep as long as possible. Also, there are lots of 24hour RPGs to compare against - it's almost a standard, whereas any other formats do not have many examples. This isn't a reason why not but it might be a good reason where there isn't much pick-up.
of course I would love to see a 24hour tag challenge. Where you sign up for a team, one member start and after 24 hour its passed to another. You'd have to deal with loss of control over the total of the game.