This is a simple script for servers which support the special ban ~q: prefix (Unreal supports this).
Typing /silence nickname minutes will silence them with a message for the stated number of minutes.
It removes their voice if they have one and replaces it after the time is up, if they had it.
Thought you might like to use it. :P
(requested script)

alias silence {
  if ($2 !isnum) echo -a You must specify a time in minutes.
  elseif (!$address($1,2)) echo -a Could not find an address for specified nick. Try typing /!who or spelling the nick correctly.
  else {
    describe # silences $1 $+ , therefore resulting in a loss of speaking privileges for $2 minute $+ $iif($2 != 1,s) $+ .
    .timer 1 $calc($2 * 60) mode # -b $+ $iif($1 isvoice #,+v) ~q: $+ $address($1,2) $1
    mode # -v+b $1 ~q: $+ $address($1,2)
    .timer 1 $calc($2 * 60) describe # $1 regains the power of speech. It would be wise not to be naughty again, $1 $+ ...
  }
}