My favorite collect - indeed, the first one I knew - is the week before Advent:
STIR up, we beseech thee, O Lord, the wills of thy faithful people; that they, plenteously bringing forth the fruit of good works, may by thee be plenteously rewarded; through Jesus Christ our Lord. Amen.
It is this collect, and the preparations of Stir-up Sunday (in a culinary sense, at first) are what first began my pull away from Quakerism and toward the Church. At first, it was tongue-in-cheek. Now, I'm very serious about the importance of the Christian calendar and the true Church. We conclude this year with a farewell to our old life, and a look forward to the further journey home.