Almost exactly the same thing happened to me. I went their for the contest, it was in some weird back aisle on a folding table. I had one minute to assemble something out of a jumble of pieces. I managed to put together a pretty neat hover bike thing. Once the contest was over, I was informed that it was a competition to see how many pieces you could unartistically slap together as fast as you can. I wasn't close to the record. I lost and couldn't have another chance, despite the fact that no one else was in sight.

I did get Stunt by the Barenaked Ladies after that, though.