Race used bicycles plus a few other special ones.
1986 US national team team pursuit
Stamps, especially the official mail stamps from the 1870's particularly ones showing defects in the printing plates.
1875 special printing foreign entry of 6c executive on 6c State dept. position 11 One of probably 4-5 sold.
1875 special printing 2c State with double transfer at the bottom. One of 51-52 sold. (On the left, the right one is normal 5,145 sold.)
Plus a bunch of other stuff, but far less seriously.
Steve B