THE FILM FANTASY WORLD OF GEORGE PAL documentary has a few clips of the original trailer for DOC. What I find fascinating is how 'straight' it's all played. Further proof that the studio botched the release.
I have a particular fondness for the DOC movie. Was all excited to see it in 1975 on a double bill with LAST DAYS OF MAN ON EARTH at the local Drive-In. The double feature was canceled. Tried to see it THREE TIMES at another Drive-In the following November (snow, car broke-down).