I love Randy and Jeff's Game Plan curriculum and I adapted this center from a lesson in their 1st grade book.
The Sound House is an activity I introduced during a regular lesson and then used as a center during the last few weeks of school. In "The Sound House" (which is just a tri-fold board that I covered in white butcher paper and had a student decorate) there are unpitched percussion instruments we have played throughout the year. One student sits in the house while the rest of the group sits criss cross applesauce in the front yard. The student in the house plays a short pattern on one of the instruments. The students waiting in the yard raise their hands to guess which instrument it was. If they get it correct they get to take the next turn in "The Sound House".