This is not your typical mission trip.
For one thing, I'll be gone for 18 months. Women serve for a year and a half; men serve for two years. (It's a long time, I know. More on that later.)
Instead of doing primarily service work, I'll be proselyting. There'll certainly be opportunities to do traditional service - as well as possibly teach English classes, or something of that type, depending on where I go - but the majority of my time will be spent speaking to people about Christ. ("Give a man a fish...", right?)
We'll work with members of the church too, teach Sunday classes sometimes and, yes, we'll sometimes knock on doors and ask you if you know you're a child of God.
Do you happen to know that, by the way? (And I mean really know it. 'Cuz if not, you can always....ask the missionaries! Or pray on your own to find out.)
Interesting details about Mormon mission work can be found here: http://www.mormonnewsroom.org/topic/missionary-program. There's also a video.