Usage: CTCP [=]<nick> <command> [<args>]
  CTCP allows you access to the client-to-client protocol used
  to perform certain client specific actions between different
  clients on the network.  The CTCP mechanism works by sending
  a specially coded message to another user whose client is
  supposed to reply with a reply message of the type, or with
  an error message, unless you sent it to a channel.

  For example, if you do:
    CTCP hop VERSION
  you will receive:
    *** CTCP REPLY VERSION from hop: ircII 2.8-EPIC2 NetBSD 1.0A special.

  You can also send CTCPs to people over an open DCC CHAT connection
  using the form =nickname, as in:
    CTCP =hop VERSION
  you will recieve the same input as above (assuming you have an open 
  DCC CHAT connection to hop.

  The <command> field may be of several types, new ones are
  introduced all the time, but there is a mechanism for you to
  find out what you can use: see CLIENTINFO.
  If the nickname is "*" the output is sent to the current channel.

See Also:
  CTCP CLIENTINFO
  ON CTCP
  ON CTCP_REPLY
