I'm not sure but what I've told this on here before, but my son came up with it spontaneously as we were driving in Utah once, and I was filled with paternal pride, so...
As you all know, the LDS church requires all its young men to do a term of missionary work before they marry and settle down. We've all seen these clean-cut young guys in suits wandering around in pairs or trios.
But recently, the church as been experimenting with letting some men stay at home and due their missionary duties over the internet. They stay up late at night and send out multiple messages and newsgroup posts attempting to convert people to Mormonism.
This is known within the Church as a nocturnal e-mission.