Sample League Question

If my league says that it begins Sunday, does that mean after midnight tonight, or after midnight tomorrow? In other words, do I need to have my changes done before 10pm est tonight or tomorrow? And, the games play each consecutive night, right?

Too late on this for you, but for the benefit of future players:

If the league says the first game is on a given day (Sunday or Monday), you need to have your roster set by 10 PM that day. I'm in a league with a first game on Monday, March 2, so I have until 10 PM on Monday, March 2 to get my roster and strategy set. The league will run overnight and you'll see the score on Tuesday, March 3.

In football, games play on 16 consecutive nights -- and more if you're lucky, lol.