I've learned that I should re-read the description of the game jam before signing up - I misread the 10 days as starting on the 10th May, rather then the 20th, which meant I only had a few days to write anything before going on holiday!
I'm quite pleased with what I did get done in those few days, though, especially as it was my first game jam, but as I only got back last night, it meant that I haven't had chance to check out more than a handful of the other entries before voting finishes :(
I'm looking forward to taking part in a future game jam, and getting the full experience next time.