On March 14th of this year, a group organized a Pi in the Sky sky-writing for the digits of pi.
As far as I know, the event was specifically setup because SxSW happened to be going on at the same time.
As a math guy, I'm generally not turned on by the digits of pi since they don't really mean anything practical to me, but I absolutely loved seeing how they did this.
Essentially 5 bomber-looking prop planes flew in formation and spewed out the gas almost like a dot-matrix printer. It was really amazing to watch!
