A "progressive" party with several "stops".
Participants spend time at each stop, eventually ending together at the final prog stop.
Often, each stop is themed.
For example, in an around-the-world prog party, each stop will have the theme of a different place.
Person 1: Hey, are you going to the prog party?
Person 2: Nah, I'm busy until about midnight.
Person 1: Well, that's when we end at the final prog stop. You should come!