If you're looking for technical chats, they usually flare up every now and then during the 'ordinary' threads.
The most recent example that I know of is the Matter/Anti-Matter reaction vs Artificial Quantum Singularity debate.
This is the General Chat section though, so if you want to chat about anything, just post it here. All the threads are open to everyone, so people will post soon enough.
The alternative is to set up a time for people to join you on MSN - you'll need their sign-in details, of course, so ask them to post them on the site/PM/email you.
I'm sure you'll find someone to chat to, afterall, we all like Trek here to a certain extent...