"Hoppy Hour" is a rabbit socialization event organized by the MN Companion Rabbit Society. This is a video from a recent one held in Golden Valley, MN.
Dougal makes an appearance about 30 seconds in.
Update: Since there's been some questions in the comments, I will explain the rules of Hoppy Hour.
The rabbits must be spayed/neutered and free of diseases. Owners must sit on the edge of the mat, and children must remain seated. The people you see walking amongst the rabbits are the Bouncers, who clean up messes and give rabbits a time out (flipping them and returning them to their owner) if the rabbit fights or tries any shenanigans with another rabbit.
If a rabbit spends too much time hiding in a box (as Dougal did his first time), the bouncer removes the box to encourage them to socialize.
You're not allowed to pick up any rabbit but your own, obviously, but if a rabbit hops over to you, you're allowed to pet it. There's a $3/rabbit fee, but people without bunnies can attend for free.