Brad Haas is having some interesting discussions with a couple of Mormon (MoMo?) missionaries.
Being from Idaho, I've had a few encounters with LDS missionaries as well. I came on too string on the first attempt. On the second, I think I actually made an impact. Hard to say since I didn't hear from them again. I'm still waiting for the Jehovah's Witnesses to drop by.
When I first started delving into apologetics, I began posting on a few message boards. I quickly found that this is mostly just a good way to get into heated debates and to feel tempted toward uncharitable comments. I've since decided that message boards aren't the way to go for me. I do better face to face or in one-on-one interactions.