Ah yes, I did some of these when I was in school and still participate in online studies even if there is no compensation.
The best one I did was at university health science center to drink absolut vodka and then a researcher determined how BAC impacted how openly participants would discuss HIV status with an actor who we knew didn’t actually have HIV for about 30 seconds. We were paid hourly and couldn’t leave until your BAC was 0 and in the meantime, participants could watch Mad Men DVDs and eat the free pizza and snacks available to sober up. I made $120.
Another one took saliva samples after a stressful event- the mock event was to spend 10 full minutes in front of a panel of fake interviewers discussing your dream job under bright lights and a camera. No matter how passionate you are, 10 minutes of straight talking without any preparation is very difficult. It was actually humiliating but I got my grocery budget for the week!