The night before CodeMash, I was up all night with my daughter who had a horrible 24-hour virus that kept her throwing up throughout the night. It made it really hard to leave her the next day. That's the first time she's thrown up, and it upset her about as much as it upsets me to throw up.
Well, the next day I made it through the keynote and most of the first two sessions, then bam! I made it back to the room shortly before losing breakfast and maybe some of dinner. I haven't been that sick in a long time. I think I got out of bed maybe 6 times in 24 hours. As a result, I missed many of the sessions I had come to hear.
Despite that, I had some great face-to-face time with colleagues and met some new people from the Ruby and .Net worlds. Try doing that at JavaOne :-).