It has been too many years since I hve done so; however, when I was in Memphis going to school for the Marine Corps, we would finish our assignments by 8:00 Friday night, start playing (usually dnd, sometimes top secret or others) and stop at 6:00 the next morning, go to breakfast, sleep until 12 go to lunch, and start the entire process over again... and that was every weekend. If a player had extra studying to do, or was involved in something else, they just didn't play- no hassle, their characters just jumped in when they returned.
As everyone had different schools of varying lengthsm it was a revolving cast; however, it was like that for the 9 months I was there... now adays, we <i>might</i> get in one marathon session ever great while, as we only play on Saturdays and I work Sundays.