Basically, the CIA did mind control experiments and used various drugs, like truth serum, amphetamines, and LSD and a number of other hallucinogens and psychadelics (even marijuana). It's strange, strange stuff. They also looked into torture techniques used by governments around the world. Eventually, they adopted a couple techniques used by Russia - self-inflicted pain and sensory deprivation. Guess where these techniques have been used recently.

Anyway, here's the wikipedia link:
http://en.wikipedia.org/wiki/MKULTRA

Also check out CoIntelPro if you don't already know what it is:
http://en.wikipedia.org/wiki/Cointelpro

It's been theorized that CoIntelPro may have even been involved with the Assassination of Martin Luther King Jr., but that's something for the Conspiracy Theories forum. Though, it is certain that they've been involved in a number of assassinations- black panther party memebers, the attempted assassination of environmental activists Judi Bari & Daryl Cherney, etc.