Imagine an online club.

You enter the site, turn on your webcam, and choose a type of dance music.

You arrive at a website with a popular song playing and bunch of live feeds of people dancing to it. There's one really big video of the favorite current dancer, and a bunch of smaller ones of the rest.  In the top right is the video feed from the DJ, who chooses the music and moderates the "club".  

Suddenly, you see the words "START DANCING!" With a countdown timer at 5 seconds.  If you don't start dancing in those 5 seconds, you will be kicked off (by the DJ).  Else, you can stay until you stop dancing.  

There's one button to go to another room at random.  That's the whole site.