A "how to turn your project into a company? should you, and why?" talk by YC (ideally, with European YC company founders, ideally in the product spaces most interesting to CCC hackers) would be awesome. The downside is it's 27-30 DEC in Hamburg.
However, looking at the current list of YC partners [2], I don't see many that might have ties to Europe, such that they'd be visiting much (never mind the imposition of giving up family/holiday time to give a 'work' talk).
Here in Vienna, we'll have an event with quite a few YC alumni on May 29: http://foundertalks.org
We do not have the means yet to make it free, however. We basically started this a few weeks ago, because we felt that something like startup school is missing in Central Europe. I guess you must have felt the same :-)
EDIT:
P.S.: After our event, I'd be happy to give you some feedback regarding what kind of questions/interestes/etc. European founders voice in such a setting. It's an awesome experiment, I'm really looking forward to it.
We have some awesome YC alum in London (and the YC community there is growing), and we're excited that they'll be joining us in July. We'd love to do something in Berlin as well.