That's right. We've got a whole bunch of people who figured out how to hack into Temple of Elemental Evil's .dat files and change the data. Apparently, it's relatively easy to edit the files containing item descriptions, dialogue, quests, sounds, portraits and the like. If you're interested in modding ToEE and would like to participate, check out the following official forum thread.

Because I sure as hell am.

The following modifications are currently out for ToEE:
Fogless Town Areas in Temple of Elemental Evil v1.0 - Download
Importing Custom Player Portraits into Temple of Elemental Evil v1.0 - Download