Bekele's little finger when he sticks it up near the end of a race when he is destroying everyone.
Other notable mentions are the piece of track that Usain Bolt was literally given after his retirement race. It is from the Olympic 2012 track. I wonder what Seb Coe will give to Bekele when he retires. Hopefully not for many more years. Discus
Mo Farah's watch that he lost in Haile's hotel