Here's one that I don't believe has been posted in this thread. It's Jocelyn Lovell at the 1982 World Championships on his unique 1 kilometre bicycle. Besides designing and constructing the frame himself, it has an ingenious, automatic shifing, two speed drivetrain of Jocelyn's own design, that did not violate the UCI rules prohibiting derailleurs on track bicycles. If you look closely, you'll see that the bicycle has both left and right hand drivetrains!
The right hand drive is the lower ratio "start" gear and it used a single speed freewheel. The left hand drive is the higher ratio and uses a fixed gear style cog that is not locked in place. This cog is mounted on an extended threaded section, similar to a freewheel hub. At the start, the cog starts to unthread itself, causing the drive to take place though the freewheel. When the cog hits a stop it takes over the drive, causing the "start gear" to freewheel.
In addition to providing a suitable difference, the two ratios had to provide similar chain tension. Jocelyn settled on 42T x 13T and 53T x 15T, which allowed him a low gear for about the first 70m. Lovell had won silver in the event in 1978, missing out on becoming World Champion by a fraction of a second and had hoped his invention would give him an advantage in acceleration to make up the difference. While, the dual drivetrain functioned as intended, Lovell was not in peak form and finished out of the medals.
Of course, the real significance of this bicycle is that it can't be photographed from the non-drive side.
