All fast periods are to include prayer, fasting and almsgiving.
For the Eparchy of Van Nuys, and I believe for all the Metropolia of Pittsburgh laity, simple abstinence from meat is required on Wednesdays and Fridays, although I note on the calendar printed by the Byzantine Seminar Press, that only simple abstinence on Fridays is noted. Strange!
Someone on another thread had asked about the how to time the fast day, and I believe the consensus was from midnight to midnight. However, that's probably just for ease of keeping track. It would probably be just as good an answer to go from sundown to sundown, or as you said from getting up until going to bed (but no fair eating in the middle of the night!).
At a social occasion, if you cannot abstain without giving offense, it's okay to break the fast out of charity. You might, however, want to fast on a different day to make up for it. All fasting is for our benefit, to help us curb one of our most basic passions. Fasting helps us to understand our total dependence on God, for without the food he provides us, we would perish.
The Apostles Fast is an ancient fast. Tradition has it that the Apostles fasted 40 days from Pentecost in imitation of Christ before they began to go their separate ways to preach the Gospel to all nations. We keep this fast also to remind ourselves that we have a mission to witness the Gospel in our lives.
