Easy,

Code:
[color:green]On [color:red]@[/color]*:text:!help:#:{
  [color:blue]mode # +v $nick[/color]
}[/color]


For help on the "on TEXT" event, type /help on text. For help on the @ prefix, type /help event prefixes. For help on the /mode command, type /help /mode. That'll get you started.