When I'm bored and happen to remember to do it, I read webcomics. I'd read them more often (since I'm bored fairly easily) but I'm forgetful. So, for the most part, I only actually remember to read webcomics that happen to have RSS feeds that work unless I've just recently started reading them.
Some stuff that I read fairly regularly:
Gunnerkrigg Court - Spacemonauts!
Wapsi Square - My favorite character is Katherine Gilchrist
Some comics I read more occasionally:
Penny Arcade - Often funny, but often too crass for my tastes.
Short Packed - Similar to PA.
El Goonish Shive - I prefer warped over crass, yup.
Dresden Codak - Just discovered this one. It has Tiny Carl Jung as a character, and Nikola Tesla turns up, so those are plusses.
And some I haven't read in awhile:
Avalon High - Largely defunct
RPG World - Defunct?
Nekobox - Essentially finished?
Eversummer Eve - It was updated so slowly that it was hard to remember, and now the archives appear to be subscription only