NCMO: Non-Committal Make-Out.
Pronounced "Nick-moe", it's entirely possible that the term predates the website, but it is believed that NCMO.org brought it into the mainstream.
Created by BYU students, the website allowed other students to schedule meetings for some anonymous no-strings attached lip, similar to a booty call, but with less threat to your oh-so-valuable virginity. School officials eventually got wind, and threatened legal action, so the site is now just a dating site of no real significance, but the practice is still alive and well, through the wonders of the Internet, thanks to these makeout pioneers of the Mormon community.