Castles in the Sky & Tipping the Scales

Castles in the Sky: The tree house collapses under the weight of snow of the roof. After meeting Frank Gehry at The Sugar Bowl, Arthur and his friends come up with different ideas to build a new tree house. The only design they agree on is the original, which they rebuild. Frank Gehry guest stars as himself.
Tipping the Scales: The school choir is excited about singing in Crown City, but they aren't excited about Mrs. Krasny's replacement, Dr. Fugue. All goes well until the road is closed and the trip is canceled. They stop at a restaurant and start singing anyway.