I'm on IRC constantly via Weechat on a VPS and Weechat-Android connecting my phone.

Servers I use: irc.tilde.chat irc.sdf.org irc.freenode.net and a few others here and there.

There's a huge amount of IRC usage in the wild still. Major projects use it, like the web-extensions project. Hobbiests have servers and channels gallore. Every programming language has a presence. There's so much to see and explore.