>This is really interesting. I can see why the Super Bowl would be a spike, but the Monday after seems strange. If anything, I'd expect it to be even lower than an average Monday, because so many people just went out the night before?

You're assuming that people who went out the night before stopped partying to go to sleep. There are going to be a ton of people who party through Superbowl, get on the marching powder, and just carry on the next day. And all the people who choose to travel and make long weekends out of it.