Believe it or not I just saw someone sling a fruitcake on the show "Unwrapped" on the Food Network as part of a competition for distance.  There were a couple of trebuchets and a modern looking viking catapult as well.

Quick clip but interesting use for the fruitcake (and sling), especially if you don't like eating it.

Sometimes ya never know where a sling will come in handy...
Brian

I would have liked to seen more of the flinging.  It was hard to tell what kind of range they were getting.  They would show a person or treb launching and then cut to the zoomed impact.

The only full shot that I saw was some guy just pitching a cube of fruitcake (with clipped edges) like a baseball.  Looked like he threw it pretty far.