I think he wants the script to ask someone for an invite, not to actually invite someone or to join when invited.

Code:
on *:text:*:#yourchannel: {
  if ($1 == !invite) { msg $nick Requesting invite. | msg SOMENICK $nick requested invite to $chan $+ . }
  elseif ($1 == !mod) { msg $nick Requesting help from a mod. | msg SOMENICK $nick needs help. }
  elseif ($1 == !forum) { msg $nick Our forum is located at http://www.google.com/ }
  elseif ($1 == !calc) { msg $nick $calc($remove($$2-,$chr(36),$chr(124)) } 
}


Keep in mind with !calc that it will mostly only do basic calculations. Also, someone can verify if that is safe how I have it set up. I removed $ and | which should prevent any improper use of the command, but there may be other things that should be considered with such a command that I'm not thinking of.

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