Junkyard Wars is a reality television program shown on the BBC and The Learning Channel. In the UK, the program is called Scrapheap Challenge; Junkyard Wars and Scrapheap Challenge are in fact the same show with a different title.
In each episode, two teams of three persons each get ten hours to build a working machine out of things found in a junkyard. Then the machines are raced to determine which is that episode's "winner". Each team is supplied an expert in that particular class of machines to help them design and build the machine; another expert serves as a judge.