New: Qalculate! (Sep 29, 2022), Platform 22.0.1 (Jul 21, 2022)
450+ real apps (49GB), 1.06 billion downloads, Please donate.
I suggest this Windows irc client to PortableApps portfolio.
This software already is in portable mode, would be quit easy to port to PortableApps format.
Official website is www.adiirc.com
requires the .net framework 2.0, it would not be a good candidate sadly however we have PChat Portable as a dedicated irc client, kvirc as well, and pidgin supports the irc protocol as well.
your friendly neighbourhood moderator Zach Thibeau
It's also freeware, not FOSS, I haven't yet looked at the specifics of the license yet, however.