Can I run top as screensaver? My employer has recently issued me a MacBook Pro to play with. I have a lot of Linux experience, but I was struck by how nice the terminal looks on the Mac in full screen mode, especially when running "top". I think it'd look impressively "hackerish" as a screensaver.

Has anyone figured out a way to make this work? Of course, I'd have to disable the usual power saving mode where the display is turned off. 

There's one project out there, but based on it's website it's very rough if it even works.
If you're looking for hackerish screensavers, the old Xscreensaver bundle was converted to OSX a while ago.

Nicely hacker type examples would be Sonar, AppleII, and Phosphor. Possible GLMatrix too.

However, to answer your question: https://superuser.com/questions/420546/osx-run-bash-or-app-as-the-screensaver

Write an applescript to run Terminal, run Top, and fullscreen itself. Then put that script into the app.