As you may have heard, United States census data becomes public record 72 years after its collection. That means that as of April 2, you can now poke through the 1940 Census over at the national archives' website.

I did this, and I was able to find my great grandfather! I put a copy of the full page headers and footers here.

(The census takers, or "enumerators", were supposed to ask supplemental questions of whomever appeared on lines 14 and 29; the supplemental information appears below. By coincidence, the person on line 29 of this sheet happened to be my great uncle Gordon. His answers, which you can see at the bottom of the page, are not particularly interesting, but there they are.)