More Quake goodness: http://www.quaddicted.com/reviews/backstein1e.html by http://www.quaddicted.com/reviews/?filtered=sock.
A large brick-style dungeon deep under ground revolving around a wind tunnel system. It has a built-in skill selection area, a large number of enemies and secrets, and comes with (optional) custom medieval items.
http://www.quaddicted.com/reviews/screenshots/backstein1e_thumb.jpg