Second boss of Bardam's Mettle. Make a GATE based on it. MGP you get is based on how long you make it. over the course of 2-3 minutes.
OR
Make it something you can only do once daily, like the mini cactpot, where you go into a special area with X other players and see if you can last up to Y rounds, kind of like the battle thingie from FFVII, cept you're running from damage, not dealing it.