Twilight Forums

Twilight works on a 6-day cycle, which consists of 5 weekdays and one weekend day. Twilight actually has a seven-day week just like the rest of us, but it's assumed that one day a week you need to rest, relax, heal, and take care of real-life stuff like visiting friends and family, or spending quality time with your pets. Since your hero isn't doing anything important on that day, it simply doesn't exist in the game, because boy that would be boring! This means that during the five weekdays (Sunday, Moonday, Thewsday, Winsday, and Starsday) there is also a limit to how late you can stay up: 7 a.m. Even if your bedtime would normally extend beyond that point, at 7 you have to go home, clean up, and get ready for work. It's a shame, but that's just the way the world works. (Your extra time will roll over to the next day, though.) The exception to this rule is Frayday night, when you can stay out as long as you want because the following day is a weekend.

290, actually.

My guess is because if there wasn't a max for it people could stay inactive for months and then use up all there turns on a frayday. Which kinda would reward inactivity.