Basement of the Brothers Strong
From Homestar Runner Wiki
Strong Bad's Basement is where Strong Bad, Strong Mad and The Cheat hang out and play the Trogdor game and watch television. Many things happen down here, including (but not limited to) The Cheat in a crisper drawer. Strong Bad sleeps on the couch, as shown in the emails "cheatday" and "other days".
The Brothers Chaps work in a room, shown in Making of Email 100, where the wall is painted with the same design as Strong Bad's basement.