Back in the day, lots of television show casts were out of control, but now, you rarely see anything other than a 9 to 5 mentality and everyone kind of goes their own way before and after work. An exception now is probably something like Vampire Diaries. They all love each other and have not reached that level of fame yet.
Probably the all-time greatest cast as far as partying went was 90210. The original one. They were out of control all the time. Shortly after that show went off the air came another show which quickly took the crown.
Before this person became a drama queen, she used to share stories about her time on the set and what exactly happened and if her career had not moved from middle C to almost A list recently I think she would have eventually broken down and written a book about what happened. The cast featured mainly unknown actors. During the first season, every female cast member except one had sex with this unknown actor who had been in nothing before, but is now a very solid, but unlikable B+ television actor who has had some really bad movies.
His favorite actress on the show was the one who got in the most trouble. A lot of trouble. This still relatively unknown actress spent the entire first season coked up out of her mind. Always a person who had abuse issues, the huge paychecks sent her out of control, but she was also someone who could be counted on to be crazy and our B+ list actor loved that and they would hook up lots of nights after she had been out. It was a year long booty call.
One of the actresses on the show was unknown at the time and crawled up to B- before slowly sliding back down to her present position of C+. She spent the first month of the show happy and fun and that is when she slept with the B+ list actor. After that month though she met someone and became an obsessive worrier who thought her new boyfriend (B- list television actor at the time) was going to leave her every second and he basically kept screwed with her mind their entire relationship.
On the outside was an actor who thought he was the best thing since sliced bread but in reality did not have as much talent as he thought. Just because you were the star of the show does not mean you are the best actor. After one year he refused to talk to just about anyone other than the producer to complain about how many lines he got. Now he usually works in movies, but his chance at above the line roles went out with poor box office performance.
There were others in the cast, including the now drama queen who started off shy but grew up fast and found herself a boyfriend which stopped her from playing in many of the games and parties that many of the other cast members indulged in on an almost daily basis. Strip poker and naked Twister while downing jello shots every 7 minutes was one of their favorite games to play and that was on set. When they started getting paychecks, the parties and women and behavior got even crazier.