Donjon, the Dungeon. Imagine you are a restless comic artist like, say, Joann Sfar or Lewis Trondheim, with many such friends. Imagine you want to keep occupied for several years, maybe the rest of your life. What do you do?
Curses, by Kevin Huizenga. A graphic novel that has impressed me quite a lot, specially the last part, devoted to a theological argument about the nature of condemnation: either Hell or annihilation. Other memorable stories concern fertility daemons and maddening birds.
xkcd – A webcomic of romance, sarcasm, math, and language – By Randall Munroe.
Brilliant online comic. Very influential, it seems. See also the very nice wikipedia entry.