I made a tramp bike as my A2 DT project. Heres a picture of it:



This was it before I finished it. The bottom bracket is high because I later added 2 CNC'd nylon chainings that were a heart shaped cam which pumped a bar with 2 cartdrige bearings that ran on the cams, which pumped a air shock with the valve open so you could vary how easy it was to turn the pedals. It worked surprisingly well! I only did it because my teacher said the bike as it was was too simple to get good marks! I couldn't find a cheap air shock though, and ran out of time, so used a football pump!

It looked something like this:



Here's it in action:

You all suck, here's proper tramp biking

looks fun
you can do it  with rollerblades as well

looks fun
you can do it  with rollerblades as well