It's something that we'd always wanted to do on the TopGear site ever since we got involved with them. It's the bit on the TV show where Clarkson and his chums put cars on the wall and have arguments about which cars are best.

It's the perfect wall-based online social media car-comparison application.

Anyway we finally got to build it and we're really rather proud of it.

You pick cars and decide where they should live on the Cool Wall. Then you get to see what Clarkson thinks and he'll either be nice to you, or more often than not take the piss out of your choices. You can also see where everyone else who's had a go put them on the wall.

You can save your wall, share and compare with your mates as well as publish out a Cool Wall Widget that you can stick on your blog or website. The system we built allows TopGear to create special one-off cool wall challenges for extra larks.

As you might imagine, it's been popular.