This is a great find. This ultra rare color film from the early days of Disneyland is the first time I can recall seeing such great shots of the Mickey Mouse Club Circus. The circus is the exception that proves the genius of Walt Disney. Opening around Thanksgiving of 1955, the MMCC featured Mickey Mouse Club performers with live circus acts but was never able to attract an audience. Guests were just more interested in the fascinating new concept of a Disney style theme park than a traditional circus.
They eventually remade the show bringing in more Mouseketeers sometimes performing with their parents and other actors dressed in animal costumes. For some reason that didn’t draw either. The MMCC closed just a few months later in January 1956 and the tent eventually made its way out front of the park to become the primary shelter for Holidayland.
Holidayland was a corporate picnic area that was the only place on Disneyland property where guests could buy beer. It also had its own private entrance to the park (approximately where the show building for Pirates and the Frontierland Train Station meet). This sometimes resulted in inebriated guests wandering through Disneyland. A problem which contributed to the demise of Holidayland.
Also, see scans of the original program for the Mickey Mouse Club Circus on this fan site for the Mickey Mouse Club.