Scrapheap Challenge

A game show where two teams of engineering-minded people are set loose on a scrapheap to build machines for the challenge of the week. The teams are allowed 10 hours at the scrapheap to build their machines and one hour of "Tinker Time" before the challenge for some final adjustments. The challenges include flight, fire fighting, throwing cars, remote-control car fighting, car-sumo wrestling, digging, building tanks and that's just the tip of the iceberg. For some challenges specific items would be given to the teams (eg, manual coffee grinders for wind powered coffee grinders) or hidden in the scrapheap (eg, steam engines and boilers for steam powered cars).

Although it is a British series, they did an American version known as Junkyard Wars, which follows the original format of the show. There are also a number of spinoffs.

For the first ten seasons, was hosted by Robert Llewellyn, with a female co-host (Cathy Rogers for the first four, Lisa Rogers for the remainder). For the eleventh series the host is Dick Strawbridge, one of the two team captains from the first series.

This final series changed the format significantly. Three teams had four weeks at home and £450 to build their machines. A fourth team consisting of the host, his off-sider and someone who competed in the earlier seasons have 10 hours and £450 to build their own machine. The home teams compete and the winning home team takes on the host's team.

Scrapheap Races and Scrappy Races Rally
Four teams build a vehicle at home that has to pass a strict roadworthiness test. Over four weeks they drive their creation to a different scrapheap each week and modify it for that week's challenge. The winner is based on points awarded (Scrapheap Races) or total time taken to modify their vehicle and complete the challenge (Scrapheap Races Rally).

Scrapheap Challenge Roadshows
A number of teams build their machines at home and then come together to compete. The winners then takes on the Scrapheap All Stars, a team consisting of people who have previously competed on the regular show.

Contains examples of:

 * Catch Phrase: Barley Pickers have a habit of saying "Proper job". When they made it to the grand final, where they versed the team that won last year's competition and their contraption tore itself apart, they called it a "Proper failure", as the other team's one also failed, but not nearly as dramatically as theirs had.
 * Crossover: There was one Britain vs USA crossover with Junkyard wars. While no British teams appeared in the US series, two US teams did appear on the UK series. The NERDS were the first (and with a later special episode, the last), The Mule Wrights were a last minute substitute when a British team couldn't travel to the US filming site due to agricultural quarantine.
 * Deliberately Monochrome / Stylistic Suck: The segments which explained the basic science and principles of the vehicle the teams had to build were made to look like an old educational programme.
 * Dueling Shows: The BBC had various tries at creating a rival programme, none particularly successful. One of these, Geronimo, was also hosted by Dick Strawbridge.
 * Epic Fail: Normal failure is par for the course, but you sometimes get this. And it's glorious when it does, such as the horribly dangerous Mini-flinging trebuchet that bent, buckled then disintegrated when they tried to fire it. A cannon built by a team of British Army officers managed to fire its barrel instead of its slug downrange. (for once muzzle velocity actually meant speed of the muzzle, rather than speed of slug at the muzzle).
 * Machines incorporating hydraulics tend to fail disappointingly (the Pink Slider seized up and ceased to slide) or spectacularly (the Mighty Muncher's hoses separated, spraying coolant and hydraulic fluid everywhere).
 * Kayfabe: The heaps have been salted with useful trash, but the most blatant was when a team found a partial roll of Mylar for a flying challenge. Whenever possible the item seeded was sourced from a specialist salvage. The crew stocking the yard also removed items that would make things too easy. This was sometimes done for purely practical purposes: for a challenge involving a steam engine, for example, improvising a boiler would be near impossible and dangerous, so a few certified ones would be 'planted' amongst the genuine junk. Likewise, that grubby old aircraft propeller you just found would have been a dirtied-up new one for safety reasons. A longer explanation can be found here
 * Occasionally averted. For instance, in the rocket episode of the Junkyard Wars version, the narrator tells the viewer point blank that solid-fuel rocket engines have been hidden in the junk. Other times, items will simply be provided to the teams, such as helium for the flying challenge.
 * Hey, It's That Guy!: It's hosted by Kryten.
 * Market-Based Title: Junkyard Wars in the United States; originally retitled, later a separate series.
 * Monowheel Mayhem: One episode had the teams constructing monowheels and racing them round a test track.
 * Not Cheating Unless You Get Caught: Teams regularly swipe stuff from each other's lots, incurring no penalty from the hosts aside from a few snarky remarks. In most cases the "Theft" was setup by the TV crew for dramatic effect, with both teams asked if they would allow it.
 * Ramming Always Works: In a game where the challenge is to break a wall down, one team got frustrated with its wrecking ball's slow performance and decided to start ramming the wall down. This led to a ramming contest.
 * Retool: The latest season is much closer to the 'Roadshow' format. Or to Geronimo.
 * Shout-Out: Because no TV Tropes page is complete without a Terry Pratchett reference, note that during the tractor tug-of-war episode, one team named its machine "The Great A'tuin".
 * Tim Taylor Technology: A lot of the vehicles in the "Scrappy Races" spinoff were rebuilt with much larger engines than they were designed for -- or, in the case of the Chaos Crew's entries, additional engines.
 * Explosive Overclocking
 * The Watson: The hosts in the earlier series.
 * Wrench Wench: Some of the female techies looked quite appealing in coveralls.