Obstruct traffic

Okay, so you start with two to four teams (or as many as you want) each consisting of one to five participants.
Then map out a grid of busy city intersections, which will become the space in which the event will take place.
Dress as astronauts, keeping you identity concealed. Make sure while you are dressed up that you have weights tied to you making in harder to walk. Carry flags (each team having there own color flags), cross busy streets and claim various cross walks by putting your flag in the way of cars.
The team with the most intersections claimed wins.
Continue your daily routine in costume.