Ask HN: Ideas for holding a virtual launch event?

I do work for an open-source project with people all over the world. We're going to be having a huge release next week, and want to make it special.

We're inviting core contributors and our best (most vocal) users to a live video call, and hoping to have a nice entertaining 30-60 minute event leading up to the v1.0 release button-press on GitHub.

Any ideas on what to actually do?

The project is about 3 years old, so we're thinking about going through some history/trivia for a little bit, maybe making some kind of a game out of it.

What else? What do people do at launch parties anyway? I know much of it probably won't work well virtually, but any advice/suggestions would be great.

FWIW, because of unpredictable quirks in our testing process and other details, we didn't know the exact launch date until this week -- hence the short lead time.