There is a level design contest going on right now where you can win these commercial licenses of 3ds Max plugins + other prizes:
The first contest required contestants to create a Source Engine Level composed of only world geometry (brush geometry) created entirely inside 3ds Max. This new contest is still about making a Source/Goldsource level inside Max, but this time you can use models, displacements, and any other kind of asset.
Visit www.angryteapot.com to learn more. Visit Wall Worm to get the Wall Worm tools for exporting Source levels from Max.