Funny level generation code

Hey guys,

I made a level generator a while back to try to generate really big levels. Got a bit sidetracked into various methods for how to actually do it. Some of the output is here, take a look if you're interested: http://fuseki.net/coillevels/

Has anybody else made a level generator? What algo did you use? Did it generate similar levels as are on here? Do you think any particular style is especially hard?

Ernie