You might not know it by looking at him, but Paul is a wicked card shark. When he's not making his poker buddies cry, he seeks out mogul-laced ski trails to hurl himself down, and within the first five minutes of meeting him he'll probably tell you the story about how he mostly landed a backflip on his skis. Lest his ego get too big, though, we can always remind him of the time he failed at a YCombinator startup, and he'll go bury his emotions in the sweet sweet taste of artisan chocolate--or any chocolate, really.
Paul's been interviewed by the Wall Street Journal, and one of his proudest achievements was giving a Google Tech Talk on compilers and programming languages. He wrote phc, an open source PHP compiler, while doing his PhD on compilers and static analysis in Dublin.