Type /away to activate and deactivate.

alias away {
if ($1 == $null) {
if ($away) { .raw away | echo -a [ away ] you're back }
else { .raw away :I'm away since $asctime | echo -a [ away ] you're away since $asctime }
}
else {
.raw away :I'm away ( $+ $1- $+ ) since $asctime | echo -a [ away ] you're away ( $+ $1- $+ ) since $asctime
}
}