Drama was a great part of Greek festivals. This is where the people actually came together to form a sort of congregation (one much like the one in your churches today) to watch plays with spiritual significance. The ancient Greeks saw drama as a sort of social confessional. When the Greeks watched the plays, the Greek was immediately forgiven of all of his secret sins that nobody else knew about. The plays had good morals that taught the audience reverence for the gods, while teaching them to be good to their family and country.
Sports were also a big part of festivals, the most famous of these being the Olympics. These games were often called holy games because they were in close connection with the gods. In fact, the Olympic Games were held at the feast of Zeus at Olympia in Elis, and the Pythian Games were held at Delphi, in honor of Apollo. There were many more games associated with many more gods. The winner of these games was crowned with a wreath of a plant associated with the god being honored. For example, the winner at Delphi was crowned with the leaves of laurel, which is Apollo's tree.
The athletes were thought to be guests of the god,
and they were under his protection in all events. The god greatly
enjoyed their display of strength and skill, but their joy was
nothing compared to the Greeks who came to watch their friends
perform at the festivals!