I've been building a fan powered feather for the last 12 months that's been a bit top secret but uses castors instead of a skirt.

I entered a random robot in April to try one of the ideas and it works, so umming and arring about finishing it off. It's finding the cash and time. I originally mentioned the idea to the robo challenge guys and they said the diversity in entrants is something they have been trying to encourage so it spurred me on.