Around 1988 I started the "3am club" at New Mexico Tech (http://www.nmt.edu/), which lasted about a year. The members were all ComputerScience majors who spent all the time they could on the systems. The meetings were at 3am Saturday morning, after hacking through Friday night. (The CS labs were usually very empty at this time.) We usually went to Denny's (the only 24-hour restaurant in town) for breakfast after the "meeting". There were no formal activities of the club--it was more of an excuse for hacking all night.
One big advantage of nighttime hacking was that CPU-hours were much less expensive. (Each student received an allowance of computer-dollars. CPU time, disk storage, and printing all came out of that account.) I believe an hour of daytime CPU cost about $50.00, which was approximately the monthly account allowance. Nighttime CPU would cost about $20/hr (evening), or $10/hr (midnight-6am).
Normally, this allowance was enough. (CS majors got separate accounts for lab courses like OS building or compiler construction.) However, I became addicted to "Moria" (a RogueLike? text-based dungeon game, similar to NetHack). In one month I used over twice the allocated amount on CPU time. Rather than lose access for a month, I paid more than $50 of real money to get the account back.
I think the Internet was an important factor in the decline of computer-lab culture. (The other obvious factor is the availability of powerful PCs.) People who used to talk with the other lab-residents were instead completely focused on their talk/forum/mud or other online communities. Some of the culture survives in "wired" dorms (which group people who want fast network connections), but that may also fade as broadband access becomes more common. --CliffordAdams.
HackingAtNight on computers might be viewed as a specific example of the more general tendency in the reaction of students who have access to rare and expensive research equipment. X-ray crystallographers who travel to collect data at synchrotron beamlines tell stories of the all-nighter, though such data collection trips happen only episodically rather than regularly. More personally, several of us would sign up for large blocks of overnight time on the 400 MHz spectrometer in the basement of Hutchison Hall, for a variety of reasons: Because the technique demands a lot of sample averaging, because we wanted to change the instrument configuration (run at a lower or higher temperature, change probes), because things were more relaxed in the evening so one could be more flexible in preparing the samples and then acquiring the spectra, and because the people who really wanted to be there were the people who tended to be there--I passed my final cumulative exam based on things I learned during an impromptu, nightime, one-on-one tutorial session.
To me the habit of HackingAtNight developed becouse if you wanted to call a BulletinBoardSystem with one node (as was usually the case) you had to call at night. Also early internet connections were much cheaper at night. So you slowly slided toward a habit of doing everything related to computers during night time. --JaakkoMantysaari
System/360 Model 75 'sys gens' were all weekend affairs. Once started, we worked until done. -- HansWobbe.
This is a little bit of a chicken and egg thing. There are advantages to hacking at night still. One big advantage is that non-hackers are sleeping and can't interrupt you. However, I was largely nocturnal before I began hacking. So were some of my hackish friends.
Ironically, this post is made at normal time of day as I am shutting down. However, in my defense, I was *working* during the night... -- BobTrower