Big air--well over 100 feet horizontal airborne--was always fun! The more passengers the better.
Somewhere around 180 on a two lane highway in Kansas was a trip! (Old US 36)
Racing against sports cars on twisty roads in the Colorado mountains driving a 4 door Studebaker was fun too! (Almost always won )
Standing on the seat and driving with 1 foot in the wheel while pulling the convertible top shut at about 50-60 MPH in a sudden hail storm may have been borderline though.
Drag racing into a one lane bridge to see who backed off may have been just into Psycho too. (Only did that two or three times a weekend for a couple of years so it may not count)
But I don't remember ever doing anything stupid.