The Situationists

1) The Situationists movement arose out of the student rebellions of Paris in 1968. The students were revolting against the French beauracracy and capitalist regimes of the day ( I believe). "How do we change the way people think? How do we get them to see what's happening and want to change it with us? "the students asked.

The decided to create "situations"--much like the 'happenings' you were thinking of, I think--to show and tell their messages. Their school of thought was led by Guy DeBoard and (secondly) Roul Vaneigm. Both of their major text can be found for free at nothingness.org. The did the things I mentioned--real life "plays" and protests involving priceless works of art--and also had many details mapped out about the way things should be. Very time consuming and not-so-palatable for a wide audience (one of the reasons it didn't catch on). Adbusters has made a spin off of situationists' ideas. If you've seen their magazine, they use well-known ads, but change them to get their message across. People don't listen bc it's too far left.