What arguments would you use to convince your boss to let you go to YAPC::EU? :-)
My new boss (8th of 12 now, I think) in 2002 asked what training courses she could send us to. I told her I didn't think there were any useful Perl courses for me to attend, as most were pretty basic and I was probably capable of teaching them myself. But then a little later I got to thinking that a conference would expose me to many advanced topics. When I suggested it she immediately offered to spring for both YAPC::NA and TPC, but I was unable to make TPC due to a previously scheduled vacation. If the company hadn't gone through a round of layoffs at the end of the year followed by budget cuts the next, I expect I would have now attended two more YAPC's.
Personally, back in the days when I thought I'd never get to attend a conference, I would have gladly provided my own expenses, lodging, and transportation if the company would have simply provided the time, and I often thought about making that suggestion. Now that I'm married and sharing a budget with my wife, however, I don't think I could afford to make that offer any more. (Well, maybe for a close YAPC.)