  Service sports include two-player contests such as volleyball, badminton, and
squash. We analyze four rules, including the Standard Rule (SR), in which a
player continues to serve until he or she loses. The Catch-Up Rule (CR) gives
the serve to the player who has lost the previous point - as opposed to the
player who won the previous point, as under SR. We also consider two Trailing
Rules that make the server the player who trails in total score. Surprisingly,
compared with SR, only CR gives the players the same probability of winning a
game while increasing its expected length, thereby making it more competitive
and exciting to watch. Unlike one of the Trailing Rules, CR is strategy-proof.
By contrast, the rules of tennis fix who serves and when; its tiebreaker,
however, keeps play competitive by being fair - not favoring either the player
who serves first or who serves second.
