For your summertime enjoyment:
The Drive-In Movie Ad Archive
(Also available, in case that breaks, at tinyurl.com/mk5eh )
Some of the ads are generic neighborhood promotions (and there are a few of the popular "If You Should Accidentally Tear A Speaker Loose" series), but overwhelmingly they're about tasty treats available to one and all. I believe most or all of them can be streamed or downloaded, and different versions are available for dialup and broadband users.