The sack on the running board trick could work well for that troublesome child, cranky mother-in-law, drunk buddy, etc.....
I had a loud stereo in my 73 wagon many years ago I recorded on cassette cool engine noise to see what it sounded like, it was of course a waste of time but hey I was only 17 y.o. Good finds.
here are a few ... a pair of wind deflectors, more window snugs everyone seems to have, some child safety door locks and a speedo powered by the wind. Attached Thumbnails
Those window snugs would probably be good things to have if you're the owner of a 64.5-70 Mustang... Cool thread idea.
the window snugs would be great to keep on hand if you have a 97 or newer buick, olds, pontiac, chevy.. for when the window regulators go out.. you can hold the window up till your ebay order comes in.