There are a variety of helicopters that have demonstrated aerobatic manouevers over the years. The most spectacular is the Sikorsky CH-53, can't get much more dramatic than rolling a big ship! I believe the S61 was the first of the Sikorsky products to demonstrate this manoueuver.
In the commercial world, there are a few known inadvertent rolls that have occurred, and the machine succesfully recovered. Many years ago, a logging S61 managed to snag a B206, after both long lines became entwined during an avoidance action. The 206 ended up inverted at the end of its long line and the 206 pilot punched off from his belly hook and recovered!
I also know of a now unemployed pilot who rolled a commercial MD500D. Perhaps the most inane activity was a pilot who demonstrated a roll in a Lama, to impress his passengers. Unfortunately the VIDEO that they shot from inside the helicopter ended up on the Chief Pilot's desk - another unemployed individual!
None of these manoeuvers are permitted in the commercial flight manuals, so the appropriate procedures are not in the public domain. So don't go rolling your R22!
[This message has been edited by Cyclic Hotline (edited 05 January 2001).]