Being a psychology major, I get to hear about a lot of good ones in a lot of different fields.

There's the one where an experimentor went out to a busy intersection and stood at the corner of the road. People would pull up to the traffic light in their vehicles and stop, and the experimenter would just stare at them. They wanted to see how fast the person would drive away from the light if there was someone there staring at them.

Then there's the "Tea Room" experiment, where psychologists wanted to learn about male homosexual patterns. The psychologist went to a public restroom where he knew a lot of gay action was goin' on. He'd note who went into the bathroom and for how long, etc, until they came out. He then followed them out to their cars, copied down their license plate number and found out where they lived. Then he disguised himself and went to the house of where these men having homosexual encounters lived and asked to interview them about their homosexual tendencies. Quite unethical, if you ask me.

And there's Stanley Milgram's obedience to authority experiment, where people thought they were shocking another person to death.