In one of the comments there's a better version of the script which I modified a bit, use this.
Code:
on *:input:*:{
  if (!$ctrlenter) {
    if ($left($1,1) != $comchar) {
      if (%lol) {
        if ($istok(lol|wb|ty|np|lmao|afk|nm|wtf|omg|stfu|brb|bk|lmfao|hb|cya|bbl|fo,$1,124)) {
          msg $active $replace($1,lol,12L4augh 12O4ut 12L4oud,wb,5W14elcome 5B14ack,ty,12T4hank 12Y4ou,np,1N4o 1P4roblem,lmao,12L14aughing 12M14y 12A14ss 12O14ff,afk,2A10way 2F10rom 2K10eyboard,nm,6N14othing 6M14uch,wtf,5W4hat 5T4he 5F4uck7!,omg,2O14h7! 2M14y 2G14awd7!,stfu,7S14hut 7T14he 7F14uck 7U14p,brb,12B4e 12R4ight 12B4ack,bk,4I1'5m 4N5ow 4B5ack,lmfao,9L14aughing 9M14y 9F14uckin 9A14ss 9O14ff,hb,13H6urry 13B6ack,cya,6S14ee 6Y14a11,bbl,14B10e 14B10ack 14L10ater,fo,12F11uck 12O11ff7) 
          halt
        }
      }
    }
  }
}

alias comchar return $readini($mircini,text,commandchar)
menu * {
  Turn Acro $iif(!%lol,ON,OFF):{ $iif(!%lol,set %lol on,unset %lol) | echo -a Acro Is Now $iif(%lol,ON,OFF) }
}
Tested and working.
Right click in any channel or query (or status) and either activate or deactivate the Acro(nym) script. Then simply type one of the words specified, such as "lol,wb,ty" and it will replace your message with a message filled with color etc

As Wims recommended, holding down Ctrl while pressing Enter will allow you to type "wb" without it turning into colors by the script, as a quick on/off

Last edited by Nillen; 20/02/15 03:26 PM.