Multipurpose Room Rentals?

We are looking for an empty room to rent for about 20 kids for a nurf battle party but are having trouble finding open, empty rooms for rent that don't come with wedding venue rental prices or that require $1M insurance policies. We would have preferred to host this outdoors but since we're targeting a mid-February weekend we thought an indoor plan would be better. We've looked at oakland parks n rec and submitted applications but no one seems to be able to give insight into availability or even fees so we're not holding our breath there. Any other recommendations? I'm not looking for generic suggestions like "look for churches" but if anyone knows of specific locations or leads that would be incredibly helpful!