The Long John Silver Center for the Performing Arts
From Monkey Island wiki
The Long John Silver Center for the Performing Arts is a theatre and cultural centre in Puerto Pollo on Plunder Island. Slappy Cromwell is found here, rehearsing and performing Speare: A Theatrical Medley. The front doors are never open when Guybrush tries them (he enters the building behind the stage), but the Pirates of Danjer Cove attend Slappy's performance.
After the Pirates of Danjer Cove steal Elaine, who has been turned into a gold statue, they bury her in Yorick's grave in the theatre. This location is revealed by activating the stage lights properly so that they shine in an X over the grave. In the Mega-Monkey version, they can also shine in the forms of Sam and Max.
The only known specimen of the prop tree is found onstage in the theatre.