Hi, Alicia, glad to see you made it over here. Welcome to TAW!
We do celebrate a number of holy days through the year. They serve as constant reminders of events through Christ's life, for example, and lead us in a rhythm of repentance and joyous celebration of Christ's birth, and especially resurrection, for example.
And I see as other have answered, we just keep the ancient terminology of Pascha, which is called in other places Easter.
We have a minor weekly cycle too, in addition to the yearly cycle. We remember the crucifixion on Fridays, for example, and yes, every Sunday is a reminder of Christ's Resurrection. We usually do have Holy Communion every Sunday, but it can also be on other days as well.