Unusual Context of a frequent flyer...
When I was traveling 75% for work, and spending as much as 16 hours a week actually on airplanes, I started keeping an @inflight context for stuff that was possible to while getting from here to there. Sure, I could have just used @computer for this, but there are some things that can be done from a middle seat in coach and some that can't. @inflight was mostly limited to things that didn't require much mouse interaction, or could be done on my palm.
One particular week I actually timed myself for various flights and found that I had spent almost 8 hours of take-off and landing where I couldn't use my computer or palm... I added a @EMP and began to include things I could accomplish during that time period including bringing material, a printed out document to mark-up or just a notebook to brainstorm in.
Luckily I don't travel as much as I used to, but when I do I still find these contexts useful.