The Scarab Gong
From WoWWiki
The Scarab Gong is a fixed device located at the Scarab Dais [25.8, 90.8] of Silithus.
Quests
The Scarab Gong starts and finishes the quest 
[60] Bang a Gong!, part of The Scepter of the Shifting Sands quest chain to open the Gates of Ahn'Qiraj. This quest is available until 10 hours have passed after the first person on the server has rung the gong.
Notes
This is part of the conclusion to 
[The Scepter of the Shifting Sands] quest chain:
[60] The Might of Kalimdor
- [60] Bang a Gong! (gate opening +10 hours)
- [60] Treasure of the Timeless One (after 10 hours)
