You could have sworn your brought an Ethernet cable, but were mistaken. The hotel doesn't have wireless.
No matter where you go in the facility where you're teaching, you need an escort due to HIPPA regulations.
You arrive at your onsite to discover the VirtualPC software you're using in class won't run properly. There's no good way to copy the 1.73G file to all of those computers because they don't use RAR compression here, they use ZIP.
Starting with when you arrived at your hotel, you've been having bowel problems, expelling rather violently and needing frequent visits to the restroom.
And somehow, mysteriously, perhaps through sleep deprivation (about 5ish hours, so not all that deprived) you're having a good day. Things are going well. Problems get solved. The cool IT guys at your onsite will just give you a network cable. Your stomach settles down after lunch, and eventually, the files get copied. The students are receptive, interactive, and generally here-to-learn. You need an escort, but at least not for the restroom. The students are good people, so it's not a big deal anyway. And the classroom has Internet, so even though you forgot the book you were planning to read at lunch, you've got a source of entertainment.
That's roughly my day so far. And I'm about halfway through (I end at 4:00, perhaps a little earlier).