Always check your nuts before you ride. You too girls! I was just coming back from a lunchbreak ride on my fixed folder to the local Barnes & Noble and noticed a slight wobble with my left pedal/crank. Turns out the crank bolt somehow loosened itself off. Perhaps from riding in my trunk and absorbing all the road bumps and potholes? Luckily my crank decided to loosen itself off once I got back to work and I only had to pedal one-footed for about 50 feet.
So don't forget to check your nuts!