Bukkit plugin Short Game Mode.
Lets you quickly set/toggle the game mode of any present or past players.

Usage:
  /gm                      # Toggles your game mode
  /gm [player]             # Toggles [player] game mode
  /gm set [player] [mode]  # Sets [player] mode to [mode], this works with offline players too

Permission nodes:
  sgm.set.*        # Umbrella node, gives access to both other and self
    sgm.set.other  # Allows user to set other players game mode
    sgm.set.self   # Allows user to set his/her own game mode