Mystery Solved. These calls are NOT coming from The Heritage Foundation. They almost certainly originate from telemarketer The Heritage COMPANY. http://www.theheritagecompany.com/
They call all the time, and hang up when I answer. I called them back - they are the "Heritage Foundation", a Conservative Organization. The girl I spoke with said that I might have heard of them on Sean Hannity or Rush Limbaugh. I told her there was a better chance that Creationist Theory is true. I asked that they take my number off, and the girl quickly said it would be removed, and hung up. We'll see...
But you do get a live person - unfortunately, as they are a "political" association, I'm not sure if the Do Not Call Registry applies to them. If they bother you enough, get groups organized on reddit, digg, or facebook, and give them the same treatment they give you. Why be scared to answer your own phone?