Looks a bit more like a tent than a tarp. Didnt know these existed, and after a quick Google discover Wiggle do them
http://www.wiggle.co.uk/topeak-bikamper ... rson-tent/

Anyone tried one?

IMHO - pointless.

It's a rubbish design. You can get lighter. And you need to use your bike to hold it up so you can't even ride to the pub

I recall singletrack tested one a few years ago ... whoever slept in it came very close to hypotheria due to the amount of condensation inside the thing. I imagine it was designed by someone who's never actually spent any time outside