Trackstanding at a stop sign waiting for the crosswalk to clear. Pavement was dry, level, and clean. Normal asphalt, not anything slippery. Saw an opening, put nealy all of my weight forward and torqued the pedals for a really strong, sprinting start. Rear wheel lost traction and spun to the drive side. I fell over with both of my feet still in the pedals. I couldn't move to loosen the straps because I was on my left arm and my right arm couldn't reach. I had to ask five people for help without anyone stopping before I could get one of my feet out of the pedals and stand up. The most embarassing day of my life ever. You'd think somebody would have stopped...