Cinco de Mayo Chihuahua Parades, Beauty Pageants, or Chi Races, have become standard annual events at Latino Festivals or Hispanic Fairs, from Tallahassee to New York City to Chandler Arizona to Brush Colorado to Yakima Washington and all points north south east and west, not to mention all over Mexico itself.
The holiday celebrates Mexican Independence and the 1862 Battle of Puebla when Mexico defeated the forces of Napoleon III.
In the USA the holiday has also been associated with labor unionization and workers' rights including rights of migrant workers.
In Tallahassee the annual chihuahua parade held for Cinco de Mayo consists of "the furry friends of the Mission San Luis."
Here are photos from the 2009 and 2010 parades, from the Mission San Luis' Photostream, beginning with the 2009 event poster up top. The chihuahua costumed as Zorro (in text) is especially appealing!
The "Rally Obedience" chihuahua cart is titled after an AKC titling event for course-trained dogs of all breeds. Another of the chis shown here seems to be serving as a burro for a peasant farmer. If I ever get to visit Tallahassee, it damned well better be for Cinco de Mayo!