Mine

on *:text:!defineworld *:#:{
if ($nick isreg $chan) { /notice $nick Sorry, but a regular user may not use this command. }
elseif ($nick isvoice $chan) { /notice $nick Sorry, buut a voiced user may not use this command. }
else {
if ($2 !isnum) { /notice $nick The wolrd must be a number. }
else { /set %world $2 | /set %time $ctime }
}
}
on *:text:!world:#:{
if (%world != $null) { /notice $nick The world is %world $+ , and it was set duration($calc($ctime - %time)) ago. }
}