a list of all rooms, recently active rooms first
General Arqade chat, wherein room ownership appears to be a fungible commodity with much lower volatility than any cryptocoin out there, and quite a bit more mod abuse purchasing power
Game development and other polite discussion. Game development conversations have priority. Please star responsibly. Be Nice applies here: https://gamedev.stackexchange.com/help/be-nice
Normally: General discussion around Ask Ubuntu, Ubuntu & official Ubuntu derivatives. For other Linux distros please see: http://chat.stackexchange.com/rooms/26/dev-chat
General chat for Physics SE (https://physics.stackexchange.com/). For MathJax see https://meta.stackexchange.com/a/220976. Don't ask about asking, just ask.
General discussion for https://codegolf.stackexchange.com | Guidelines: https://ppcg.github.io/chatiquette/
Sometimes hot, always heavy. (http://cooking.stackexchange.com/)
A room to share your art and offer feedback. Everyone is welcome.
For questions about calculus, real analysis, functional analysis,Complex analysis ... For instructions how to render MathJax(TeX) in chat see [this post on meta](http://meta.math.stackexchange.com/a/3297/8297).
Good questions raised here should hit the main site too! Fudge dice userscript: http://stackapps.com/questions/6150/
Mostly randomly generated noise. – http://crypto.stackexchange.com
The room where you'll find Stack Exchange's most productive people -- taking a short break!
Maintenance and review room for http://movies.stackexchange.com/. For reviewing posts and maintaining the site by anyone interested in helping.
One does not simply speak English 24/7. (This is the german Fork of the Periodic Table: http://chat.stackexchange.com/rooms/3229/the-periodic-table)
Product Recommendations / discussion. This room has different standards than the main Q&A site. Open discussion & opinions are welcome here; however, please do not post questions here that are on-topic for the main site.