one more.......
Chopperdude (training) with multiple requests to climb, descend, hover, taxi-hover, all in a confined area of the airport, all during the lunchtime rush hour....
ATC: XYZ Chopperdude, you are cleared to climb, descend and hover. Just stay below 500 feet, and stay over the grass. Repeat - you are to stay below 500 feet, and STAY OVER THE GRASS.