The Belly Flopper
National Infantry Museum, Fort Benning
When I walked around the corner and saw this contraption I wanted to take a ride. According to TOM, they are very uncomfortable. How does he know? He didn't serve in WWII (at least I don't think so).
Apparently, the US Army hoped to use these instead of motorcycles. Not very popular for obvious reasons and were the precursor to the Jeep we know and love today.