Oh, and I forgot to say, you should probably take out those two big blocks of code and put this:

on *:TEXT:*:#: {
if ($1- != 2) && ($1- != 3) { halt }
  if (%numgame == 1) && (%lastnick == $nick) { msg $chan 4You may not take 2 turns in a row!! }
  if (%numgame == 1) && (%lastnick != $nick) {
    set %currentnum %currentnum + $1-
    set %lastnick $nick
    if (%currentnum < %end) { msg $chan 12The number is now4 %currentnum }
    if (%currentnum >= %end) {
      msg $chan 12 $nick has won!!
      unset %end
      unset %currentnum
      unset %lastnick
      unset %ender
      set %numgame 0
    }
  }
}