A necessarily late night quest to the closest/farthest 7-11. At least 3 of the four derf meisters must be involved.
For every extra 7-11 hit up, a prefix must be added, i.e. double, triple, double-double, etc.
Douchebag: Wait, what's a derf run?
Derfmeister: WHAT'S A DERF RUN? Why, it's the most wonderful magical thing of all. And it only happens once a year, every week!
A journey taken with friends more for the company than the eventual destination.
1: Hey you wanna walk to 7-11?
2: Dude, it's like 2 miles away - let's just drive.
1: Naw, man, it'll a derf run, we can talk about stuff.