The following answer comes courtesy of Barney Vinson, gambling humorist and a crap dealer extraordinaire for a long time. Author of the Huntington Press title Casino Secrets, Barney has recently submitted an entirely new edition, which should be published sometime later this year.
"A hop bet is a one-roll wager on any dice combination. The point is 10 and you want to bet that the next roll will be a 6-4. Simply toss a chip to the stickman and say, "Six-four hopping." The payoff if 16 for 1 on any hop bet except doubles. Any hop bet on doubles pays 31 for 1. The house edge on non-doubles hop bets is 11%; the house edge on doubles is 13.89%. People love 'em, though."