xkcd is a webcomic created by former NASA roboticist Randall Munroe. His drawings are published under a Creative Commons license and you need no permission to reuse them for non-commercial purposes, just provide attribution to xkcd.com. New comics are published on the site at midnight every Monday, Wednesday and Friday. Here are some samples from the collection archives, click on the images to visit the source.
Digital Rights Management
"If you think the purveyors of DRM simply want to protect artists, check out chapters 13 and 14 in Free Culture, by Lawrence Lessig. Their goal is the elimination of all culture they don’t control."
"How Big Media Uses Technology and the Law to Lock Down Culture and Control Creativity" Lessig.
There’s more info about the characters, themes and content style (Nerd/Romance Humor) at Wikipedia xkcd
You can also find lots of interesting things to see and do in the Forums including other artists sharing works under Creative Commons.
Here’s the Comic Feed: http://xkcd.com/rss.xml
"I’m waiting for the day when, if you tell someone ‘I’m from the internet’, instead of laughing they just ask ‘oh, what part?"
Resources for Drawing, Cartoons, and Webcomics