With out clothing on.

Naked.

I find that a cordial no thank you tends to do the trick. If they persist, simply explained that it is hard to believe in anything without evidence. Remember if they're knocking on your door that typically means that they are true believers. Therefore you have just as much of a chance to educate them as they do you. You have made your decision based off of empirical data and lack of evidence and they have chosen the contrary.

I believe there's an invention that specifically targets this particular situation- it's called "a shotgun" XD

Seriously though, I just politely tell them that I've already got my own beliefs. They can have theirs, and I can have mine. And I don't accept any literature from them unless I think I can get a good laugh out of it XD

I tell them I once knew an elder from the jehovah's witnesses. i'm all good with that.

I just sit on the other side of the door and knock back in repeat. (I really just made that up but it sounds like a fun thing)

Answer the door wearing nothing but a rainbow wig. I then invite them in, since "the festivities are just about to begin." I honestly don't know what I'd do if anyone accepted and followed me into the house.

Answer it naked

It depends on my mood. Some days I simply politely tell them I'm not interested. Some days I tell them to "fuck off" and then there are those days I'll answer the door butt naked and invite them in. If they are crazy enough to accept my invitation at that point, I'll debate them until I grow bored and then ask them to leave unless on the off chance I perform a successful "conversion" LMAO!

I simple say that I have way too many more important tasks to be accomplishing than to engage in a battle of wits with a defenseless person.

I answer the door in my shorts and a bottle of liquor in my hand.

I have fun with them. I offer to give them 5 minutes of my time to discuss their god if they give me 5 minutes to discuss my atheism. Then I politely close the door and say 'let's not even waste each other's time'.

I am pretty tolerant, but if I can brush them off, I will. Sometimes I just tell them I am an atheist, and this can get an interesting reaction. Other times I say I don't discuss religion with strangers. Once upon a time I became friendly with an LDS gal, and she would stop by regularly. I was always polite but never took her up on her invitations. Another time a Baptist minister who lived nearby stopped at my house, and I told him I was Buddhist. He proceeded to put down Buddhism, which I thought was very foolish of him. Now I live on a boat, and I don't have this problem. No door knockers of any kind.

sometimes I just listen to what they have to say , thank them and say good bye.Its intrusive but they can still have their beliefs. If I am busy I just say so.

I say that I am an atheist and that there is no God - they turn and leave.

I tell them I come from a family of seventh day adventists. Most run away on hearing that.

Not interested.

I actually had a nice chat with a crew of Mormons who really wanted to know why I had no beliefs. It was a mutually respectful experience. Other times I had to be very direct.

I try to present reasoned argument and intelligent rational discussions with the door-knockers but with little effect! Once those eyes glaze over......

I tell them that I'm an evolutionary biologist and that I'd love to have a chat

If I have the time I enjoy the door knockers because most of the time I know more about their religion than they do. When it comes to Mormons I ask them if they are wearing their "holy" underwear. They get nervous, especially when I ask them to share the vows they took to become an elder. I tell them that I think it is kind of dishonest to ask me to believe in something that they can't tell me completely about. I ask them if they were going to buy a care and the salesperson told them that he/she was not allowed to discuss certain things about the car until they bought it. They answer that they would not buy the car. I say to them that the same issue is true of their religion. How can I truly understand an "buy" it if they can't disclose key parts of theirs.
I use a different approach with Jehovah's Witnesses. I ask them if they are total vegetarians or vegans. They say no they are not. When I ask them about not taking blood into their bodies via transfusion, why do they stop there? If they are not to take blood then they must be vegetarians to be consistent. If they, persist, which they usually don't, I have them open their Bibles to the one place in the Bible in Corinthians where it says that the Christians were not supposed to drink blood. I show them that the context had nothing to do with blood, but with partaking of food offered to idols. Then, I move to more direct reasons why there is no Jehovah, showing them that their argument from their proposition is not provable and the burden of proof is on them. For some strange reason they tend to avoid my door after that.

They are like predators in the sense they look for psychologically weak people who are easy to convince and brainwash. I tend to just get rejected by religious people automatically. But its fun to play religious too. Its a sort of fun game of fantasy discussions.

''I'm sorry, I'm agnostic, have a good day''

I recently had a man who insisted that the world is going to hell and the only way to fix it was through his religion's version of xtianity- Well, I explained to him about the 7 Mountains Mandate, the religious right, dominionism, etc, and gave him much to think about as dominionists have already beat him to the "we'll fix the world by dominating it" idea.

Years ago I used to tell them not to come back or I would cast a spell on them. Quit doing that as it seemed really mean.

I don't encounter evangelical Mormons much, but the Witnesses come around my neighborhood on about a quarterly basis, as near as I can figure it out. I know the opening of the canned speech about as well as they do, so when the spokesperson comes to "...and we'd like to share," I break in with a smile and "And I wouldn't be interested." Beyond that, I just am politely firm for the next couple of lines, they politely thank me for my time, and we part company. I've found that works better than antagonism or explanation.