Prayer Captain - Take responsibility for an eight-hour shift, calling people the day before to remind them of the time they signed up for and calling substitutes in case someone doesn't show up for their hour of prayer.
Security - Take responsibility for a three-hour shift in the night, being present in the hallway outside the prayer room to ensure that room is secure for those praying.
Substitute for Someone Praying - Be available to be called to serve as a substitute if someone is unable to show up for their hour of prayer.
Substitute for Security - Be available to be called to serve as a substitute if someone is unable to show up for their security shift.