Tumble bus
A tumble bus is a full-sized United States school bus that's been converted into a mobile gymnasium. They are often equipped with modified and smaller versions of most equipment found in gymnastics centers. Often, tumble buses offer weekly classes, as well as events and birthday parties.
The name "TUMBLEBUS" is a registered trademark of Tumblebus Incorporated, US Reg. No. 3,418,197, issued April 28, 2008, for providing instructional gymnastic and physical education services to children via a mobile gymnasium, and for retail store services featuring retrofitted buses containing gymnasium and physical education equipment. As an unregistered mark, it was the subject of a trademark lawsuit, decided in 2005 by the United States Court of Appeals for the Sixth Circuit, in Tumblebus, Inc. v. Cranmer, 399 F.3d 754 (6th Cir.), cert. denied, 546 U.S. 824 (2005)..