I’m flying to Seattle in a few hours, and it is a ~two hour flight. Anyone have any good ideas for a good paper to print out from the Arxiv (or elsewhere) to read during? Anything to keep me absorbed during that tedium? I fly back on Monday, so I suppose it could be a 4 hour paper 
Ars Mathematica
Dedicated to the mathematical arts.
A quick glance at the number theory section on Arxiv yielded this:http://arxiv.org/PS_cache/math/pdf/0606/0606316.pdf. It looks pretty straightforward and possibly interesting. But I don’t know how you can think on flights. I can never manage that.
I find flights are the best time to think. N hours when you’re confined to a small space with little to distract you. I think I’ve had some of my best ideas while flying. In fact, it was a running joke at my old job that if a tricky problem needed solving they had to send me on a long flight.