Ask HN: Any startups working in the event/venue space?

Over the last two years, we've hosted quite a few Hackers & Founders meetups here in NYC and we're always stuck looking for a new venue when it rains/bad weather. We usually meet at Shake Shack in Madison Square Park, but by the time the weather changes, it's too late to organize the group to come to another location. Posting quick tweets helps, but it's not the ideal solution to message and inform the entire meetup group.

Are there any startups solving the problem of easy discovery/booking of large meetup space (~50-100+ people)?

If so, please message me!