We present a full system for online control of multiple quadrotors. Rather than following scripted directions, our system interprets user instructions and modifies quadrotor behavior online, allowing a user to issue instructions at any time to easily control and modify flight. Handling multiple quadrotors is done through grouping to allow a user to reduce a number of individual robots into scaleably sized collectives as needed. Instructions are specified from a simple enumeration of potential action combinations governing formation shape, flight speed and style, and overall group tasking (travel to target, aim spotlight, etc), which combinatorially yield over 8000 possible behaviors. The system interprets all user commands into dynamically feasible, non-colliding trajectories, and results are shown for over 100 behavior instructions issued online to a multi-quadrotor hardware system used for a theatrical performance.