Starting a simple tennis league. The standard tennis ladder is old, but what I ran into at one of the local clubs here, Le Smash. They run a league with promotion and demotion--relegation and promotion. Every two months, they run a league with four to six player, you schedule on your own, and tally the record at the end. The pros also play in to increase the competition and as an incentive.
The league can be divided into three leagues--with each league having 4-6 players. The top league will keep half of the players with the three lowest getting dropped to the lower league. The middle league will put two-three up, keep one there, and move two down. The bottom league will move half up and keep half.
The players' wins convert to points for the masters.
The league is free, but the player split the costs for tennis balls and court time, but now you have approximately 20 players in your league playing ten matches a week--the matches usually take two hours. They will come, eat, drink, and relax. There's more traffic and people will buy things--I buy wrist bands, clothes, and socks sometimes.
It makes the club more alive and interesting to see who's playing.