It just occurred to me that you could use Blackberry's as batons in a sense and touch relay instructions from each person to the next on where to go and who to NFC next. It could work in the same way as some of those GPS games. You could have teams all starting touching phones with the first race official for a clue to get to the next official. Then the starting whistle would get them all going (all wearing black BlackBerry T-shirts). Each interval race official along the way could be located in a public place wearing a luminous BlackBerry t shirt) and would NFC first come first serve to each team to give them the clues they need to get to the next official with tags.
With each contestant wearing a shirt and the race officials being in public places also wearing luminous shirts, this would be a great marketing stunt in large cities with good public transportation networks. Each person could get a small prize at the end for competing in a way that helps BlackBerry and the winning team would get a phone of their choice (Z10 or Q10) for each member. BlackBerry might even be able to persuade NFC to sponsor it.
EDIT: or for inclusiveness any NFC enabled phone could allow someone to enter.