I observed a fellow parking his bike near the Boston Public Library. There was a bike rack with two empty spots located three steps from where he was, but instead of going for the bike rack, he locked his bike to the garbage can that was right next to him.
A prime example of taking the path of least resistance. The two interesting points of this case though are A: he chose to put his bike next to the garbage, and B: he had to puncture the garbage bag to lock it.
For another example of creative bike-locking involving a garbage can, see Usability Observation #4.