For many of our parties/functions(engagements, mehndis, Qur'an khanees) we have some dayks delivered. Usually they have biriyani/pulao, or a quorma, with your choice of meat or chicken. They also have sweet dishes like zarda(sweet, multi colored rice with all sorts raisins/coconut/little sweet colored bits), or kheer(rice pudding).
About an hour before the party starts the dayk wala comes by the house with the back of his truck full of dayks for his deliveries. He drops off your pot(s), and then goes to finish his deliveries. The waiters take over during the party and transfer the food to the buffet line, they are always busy carrying hot trays of food back and forth!
During the month of Muharram here in Karachi(specifically the ninth and tenth) people often fast. Commonly in our area the dayk walas prepare large amounts of haleem(kind of like a savory porrige, made with grains, lentils, and meat), which people will buy to feed people who are fasting, or donate to masjids.