I love technology. Click through for more awesome quadrotor video from the U. Penn GRASP lab:

Yes, quite cool. Here are a few ideas:

1. More quadrotors!
2. Adjust the flight pattern to combine rotation and all three directions of travel in one or two combined movements instead of many separate movements. This one might be a bit tricker to implement effectively.
3. Give them the ability to self-dock in a series of charging stations. Probably trivial to make them dock at a particular location (like one of, say, three charging stations). But to have a battery that can be charged quickly enough to be worthwhile — that might be somewhere in the future.
4. Give them more parts to build larger, more awesome structures — like a shrine to our Robot Overlords.