You can copy stuff. Really. But you can't sell it.
If you copy stuff and use it in a public space (ie your website or dorm lobby or myspace page, even if only your friends will ever see it) you have to include a brief and obvious bit of text attributing the work to me. It can be as simple as 'Awesome art from Liz at Spiral-Bound Sketches.' See how easy it is to be an upstanding citizen?
No remixes. But if you contact me and ask if it's okay, I might waive this condition for a good cause or a neat project.