This is why I prefer this method for a graduation celebration than the Disneyland method where everyone is so spread out and intermixed with kids from other schools.
Yes we have one. Location not a secret but it’s about 40 minute bus ride away. Typically the night goes like this.
- graduation at 5 pm
- groups of friends gather with family at a country club or restaurant for dinner. Typically it’s groups of 4-10 friends. This generally is from about 7-9 pm. The kids , especially Girls exchange gifts.
- the kids all go to one of the friends home where they change out of their graduation clothes and put on jeans or sweats.
- At 9:45 they meet at the local rec center and are taken 40 minutes away by bus for a school sponsored party at one of those game places.
- At 3 am the kids arrive at the beach and have a bonfire and breakfast as part of school sponsored party.
- At 5 am parents pick up kids.
Our school is a large (550 in grad class typically) mostly upper middle class suburban school in Midwest…the event is paid fir by the kid but anyone who can’t afford it is paid for by donors.
Out HS has an all night grad party that is at a top secret location. Kids take a change of clothes to graduation then load on buses from the grad venue. D went back on 2012 and S is attending this year. The cost this year was $175 with scholarships available. It seems like D’s was a bit less but I don’t remember exactly. I think they are a great idea and beat kids partying on their own and driving around at night - or being locked at home having no fun.
Last year our high school had an all night grad party at the local community center. Very similar to what has been described. The graduation ceremony was earlier in the morning. We went to lunch and she came home and took a nap. Tickets were $50 but it was worth it. I am not a fan of staying out all night but I insisted on her going. (just this one time) All the graduates received a take home tote with coupons and a chipotle g/c. Also daughter won $45 in the money machine where you grab money that is flying around in an enclosed space. There were some grand prizes like an ipad and a $500 mall g/c. The students got tickets that they used for raffles to win these prizes. She had so much fun with her friends on rides and playing games. Everyone got a senior t shirt to wear and there was so much food. Most importantly it was supervised so I felt it was safe. During senior week the students went to an amusement park two hours away for the day. She will always remember senior week and all the fun that she had. She had not planned on going but was really happy that she had.
We have an event like this after prom. The kids say it’s more fun than the actual prom.
I always wonder about grad night stuff. Most people here have family etc in town for the graduation and go out to eat after the ceremony. I don’t know how Id feel if my graduate ditched his grandparents and spent the night out (and the next day sleeping!). 
Not all grad nights happen the second the graduation ends. Where I went to school, grad night started in the late evening. Plenty of time to have dinner with the family, and then go to grad night afterwards. Not the case for all schools, I’m sure, but I would imagine that it’s not unheard of to have grad nights start later in the evening.
Our kids had to report to the high school at 5:30 pm. They were then bussed to the venue where the graduation was held and the ceremony started at 7:30 pm. The ceremony didn’t finish until about 9:30 pm (speeches and 550 graduating). The parents then had a chance to take pictures and give the grads a change of clothes, then the grads all boarded the buses to the party location. This all happened on the Thursday before Memorial Day weekend, so I think most people who had family in town planned their family celebrations for the holiday weekend.
D1’s school had a senior day. There was a dinner followed by a cruise around Manhattan. I don’t remember if it was an all night event. D2’s school had a senior weekend sponsored by the school, a trip to a beach resort organized by parents, and a barbecue after the prom.