If you're currently on a quiet holiday, suffering from a non-debilitating but house-binding condition or idling away your notice period doing as little work as possible, here's a challenge: you have until Saturday to design a flying machine to launch off a 6m high platform and plunge into the Serpentine for those wacky chaps at E4 who've been given a place in this year's Red Bull Flugtag. As the current UK champ Tim Simpson......