I'm having my freshman check out this site run by the American Museum of the Moving Image, which brings together every presidential campaign t.v. commercial since 1955. I'd heard about the site on NPR back in 2004, and I used it to great success in the previous incarnation of this class--but I'd forgotten how awesome the site is. The ads are, of course, the real attraction, but the site is also beautifully set up and very navigable.
It's a total procrastination device, but such fun. (Maybe I'm a sicko, but I can watch Johnson's "Daisy" commercial all day long.)