It’s easy to start up an improv group, since the only requirements are an empty space and perhaps some lights. Everything else is created from the imaginations of the actors and audiences.
The Performance Space
More specifically, you need a space with good visibility (no obstructing pillars), a number of chairs for the audience, and a few chairs for the performers. It’s important that the space be the right size for your audience! You’ll have a much better show if you have 40 people squeezed into a room that comfortably seats 35, than if those same 40 people are rattling around in a room that seats 150.
You may want to consider having a concession stand with pop and snack foods. Once you’re well-established, you might even start merchandising (T-shirts, cast photos, etc).
It’s easy to start up an improv group, since the only requirements are an empty space and perhaps some lights. Everything else is created from the imaginations of the actors and audiences.