/me is yet another undocumented feature in the universal instant messaging client Trillian. In an IM conversation or chat on any medium (not just IRC), you can type "/me roXors" to display "* Twinxor roXors". This feature is part of Cerulean Studios' apparent plan to create the one true instant messenger, despite the fact that the standards for the official clients don't include features like this.
GAIM and kopete have implemented this as well. Thanks, ocelotbob.