"out of sight" ("outta sight") is a colloquialism that was current in the late 60s and early 70s (a period colloquially known as the 60s). It may be older, I don't know, nor do I know its origin. It means "great," "fantastic." If you really liked a woman, you might say "that chick's outta sight." Or, if a news item said Nixon got a pie in his face, you might just exclaim, "Outta sight!"

Something would be less than out of sight if it was, well, less than out of sight.

A "booby prize" is the prize you get if, instead of coming in first, you come in last. I guess because you're the "boob;" though I've never heard the word specifically used in that way, it could be -- a "boob" is, essentially, a loser.

The meaning you suggest, that the male party to the date is a boob, would be a double entendre (as would the meaning that Mr. Sharon is a boob). I don't read it that way though. To say that Sharon is the booby prize though, is an insult to him. [disclaimer: I add the last sentence only for the purpose of a complete answer and clarity]