22 hours straight for us.
We arrived at 10:30pm on 7/16, and didn't make it to the taxi at DtD until 8:30 on 7/17. (We started at DL until closing on Saturday, sang "Happy Birthday", then headed directly to the line-up.)
Frodo Potter and I were awake the whole time - not even a snooze. I'm more of a zombie this morning than I was yesterday, but I think that's due to running on pure adrenaline and excitement. (Plus a little bit of pixie dust and magic.)