The Pidgin IRSSI Features plugin by Gary Kramlich and John Bailey contains a hard-coded “Easter Egg” which will spam all open conversation with a “Happy New Year!” message if Pidgin is running at midnight January 1st. John Bailey has confirmed this “feature” is intentional. The behavior is present in the pidgin-plugin-pack package for Ubuntu. It has apparently been part of the plugin since its inception.
Some may find this easter egg as whimisical as its authors apparently intended. Personally, I find it to be an unprofessional abuse of my IM credentials and identity. When we as users turn our logins and passwords over to a social software client, we implicitly trust that software to safeguard our our identity. There is a reason people get irate when a Twitter app spams all their friends with messages without their express permission. Impersonating a user and spamming their friends is a violation of trust.