The people from are giving 5 Blizzard Worldwide Invitational gift cards, unfortunately just for the US players. The gifts entitles the WoW players to a beta key for Wrath of the Lich King and an in-game pet, Tyrael.

The organizers will give the beta keys and pets to the winners of a two level one races. Now let me quote the website about the rules and the starting time of the races:

“The main rules are simple: You must be level 1 and have no weapons or armor equipped. Anyone seen to be wearing anything will be politely removed from the race. If you die or get disconnected during the race, you will be removed.
The starting time will be 18:00 PST (server time) on Friday 12th and Saturday 13th September (incidentally, that’s 2am here in England… see what we’re willing to do for you guys??). For those of you in Australia, that will be Saturday and Sunday morning, times vary depending on where you are.
We will be announcing the servers and starting positions before the races begin, so check back often!”