Hi, I participated in Paris Startup Weekend last december. It was amazing, I met very interesting and competent people that I still see today. And best of all I actually built a startup: http://www.submate.com we just launched the MVP 2weeks ago and it's a tremendous experience. I can assure you that we are now a real startup ! We have been selected at Plugg, The Next Web and Nonick and we are actually raising a seed round.

Startup Weekend is great !! And even better if you understand that everything actually start the next monday morning...

(in my experience, there were more marketing/biz guy than dev and very few designers)