A few places to consider include WeWork Office Spaces & Coworking. With branches scattered throughout midtown and uptown, they are one of the best known coworking spaces with meeting rooms in Atlanta. Amenities include meeting rooms bookable by the seat and hour, bike storage, espresso machines, and private offices.
The benefit of booking an office at a coworking space is that you aren't locked into paying for rent when you don't need the space. You can book the office on entirely flexible terms; it's available when you need it. And when not required, you aren't paying for it! Just be sure to book ahead as meeting rooms in coworking spaces are always in demand. Otherwise, you might have trouble getting a room at the last minute.