There's a contest running over at the REoL TOUGH site. The winner gets his hands on one of their latest Doom II or Q3:A map prior to its release.
A demo of the GI Thunder Strike project for Doom II has been released. They're also looking for people who know their way around BEH files and/or ZDoom support. If enough people join up they might form a proper TC group.
Allies is the name of a new project by Isle. It aims to be a 32-level ZDoom-based TC with new sprites, extensive scripting and thorough storyline. Good luck :)