Cowboys ride their ponies down the main street (which is not named Main Street) in Buckeye Saturday morning during the Buckeye Day Parade. People from Arizona Public Service (APS) were pulling a huge inflatable Arizona flag behind the cowboy. The event was a part of Arizona's centennial celebration of statehood. Arizona became the 48th state in the union on February 14, 1912.
The state is marking its 100th birthday with parades, fireworks, mass weddings (since the centennial is on Valentine's Day) and other parties. It's a big deal, since this only comes around once every 100 years or so.