A local theatre was presenting their Halloween Show and needed to cut off an actor's head. They specified that it should be VERY visual and he should NOT (apparently) survive. Dan warmed up his creativity and developed "MARTYR."

Basically, the actor to be decapitated kneels behind the stocks and places his head through the opening. A rope can be threaded through the iron rings and looped up over the neck to keep the head in place...should he choose to chicken out.
The executioner stands at the ready with the BIG knife. He lays it on the back of the victim's neck...in FRONT of the stocks...and makes a slicing motion. With no more cover than that, the actor's head simply falls off into the basket. The stocks and knife are covered with the actor's...shall we say "residue?"
The prop is about 33" tall by 24" wide and fabricated from plywood -- carved and airbrushed to appear as though this particular bit of lumber has been around a while. The play is set in about 50 A.D. and according to resident Archaeologist (yes, we have one), we only get an A- on this prop because the knife isn't Bronze. <sigh>