On a balmy night not long ago I was walking down Calle Durango and heard a woman scream. I turned and saw a slender young thing in a pink dress, a plastic cup of something in hand, inside this bus celebrating with her friends. She did not seem particularly happy about me taking her picture, but I did get a couple of shots of the vehicle, which was marked "Boda Bus." For the Spanish impaired, boda means wedding.
If you go to the Boda Bus web site, you will find out that the business was started by a couple of guys who were one day part of a wedding party, to which they arrived late -- an incident they vowed would never happen again. They offer various services, including bachelor(ette) parties, one of which I believe I witnessed that night. They also offer tours of the city, trips to soccer games, and transportation to actual weddings. You could probably negotiate to get hitched on the bus itself. Let's just say it's a novel idea in a city with a perennial traffic problem.