From Halopedia, the Halo wiki
It is, essentially, a hole with a flag in it surrounded by grass. If a golf ball touches the green part, it rolls up and into the hole.
- Some gamers originally thought that hitting the Golf Ball into the Tin Cup the game would reveal the location of the hidden skull in sandbox, but Bungie later denied this and claimed that you would have to search for the skull as you would with any other Halo 3 skulls.
- When a golf ball comes on to the green it automatically rolls in if you don't interfere with it.
- The flag on the Tin Cup has a grunt head and the letters PGGA (Professional Grunt Golfing Association).