I remember quiet well being on IRC all day long after school when I was a kid and we finally had internet access. As we have been running Windows ME or something like that, the obvious choice was mIRC back then.
Recently I stumbled across WeeChat, which is an IRC-client for the command line. Running WeeChat in a tmux-session on a cloud machine is really handy, to avoid missing something 😀. See Cloud Free Tier
How to install
As simple as it could be (on Ubuntu 20.04):
$ apt install weechat
Some hotkeys (aka key bindings), which are useful:
Get a full list at https://weechat.org/files/doc/stable/weechat_quickstart.en.html#key_bindings
See also IRC Commands