Mexpat is an international community of foreigners living in Mexico. Every month or so they hold an event at a bar or restaurant in town. I've attended twice: once in May and once this Thursday, and it was a great experience both times.
In May, Mexpat was held at a lovely wine bar called Tinto y Blanco. I was surprised to find a real melting pot of nationalities and ages. I met several young women in the translation industry and swapped cards. There were gringos, Canadians, Mexicans, Germans, and others from all over the map.
Panoramica, a trendy bar set between two Indian restaurants. It got off to a slow start, but 50 or more people showed up by 9:00 and it kept going. I met a Bostonian retiree who just moved here in December, a Canadian member of the philharmonic orchestra (who I unintentionally offended for being Canadian and a musician, respectively--sorry, Chris), and a girl who works for a local organization that gets kids off the streets and into school. I also ran into plenty of people I met the last time around. Overall, a great atmosphere and fun time.
Mexpat has a website and a Facebook group: I'd recommend signing up for both, and coming out the next time around. See you there!