I think my favorite weirdness from Mormonism is celestial marriage. Not only can you get married in the Mormon church, but you can be even more bound to your spouse, by, in effect, marrying your souls together. So you and your spouse will be married for all eternity, in this life and the next. None of that depressing, "Til death do you part," bit.
http://en.m.wikipedia.org/wiki/Celestial...#section_1
http://en.m.wikipedia.org/wiki/Celestial...#section_1