I'm working on my Lang.net slides this weekend, and I just realized that I forgot to send out a link to our latest DLR hosting spec. Written by the incomparable Bill Chiles, this is a remarkably thorough guide to our hosting API.
If you're stepping through our sources, at some point in time you'll run across scary types like ScriptHost and friends. The sources don't help much here, but page 14 of the spec sure does :) Enjoy.