Log on to the official "MythBusters" website at dsc.discovery.com/tv/mythbusters/
Click on the tab near the middle of the horizontal menu bar marked "Submit a Myth." This will take you to the "MythBusters" message board.
Sign up to become a member. You can't post on the message board until you have created an account. It is free and required to submit your name, birthday, email address and a password.
If you merely have a question about the show, choose the "Science and Myth Questions." To submit a myth, choose from several different categories such as movie myths, viral videos, historical myths, military/weapons myths and a section for myths that do not fit anywhere else. Below each section is a short description that will assist you in deciding if this is the correct area for your myth.
Make sure that your myth is not a duplicate. Click on the "Find" button and type in the the keywords of your myth in order to make sure that the myth has not already been posted by another person. If it has, you might want to think of another questions, but even if it has appeared previously, you can still post your myth.
Click on the "New" button and from that menu, click on discussion. A box will pop up and this is where you will type your myth. According to myth posting tips on the forum, your myth will have a greater likelihood of being selected if it is written without spelling or grammar mistakes. Additionally, providing an explanation of the myth's origin will also increase its chances of being picked for the show.
Post your myth. The "Mythbusters" hosts do not read the forum, rather the show's researchers find myths that they feel would be good for the show and then present them to the production staff.