If you're with a group, and you want to have some inexpensive fun that could produce a hefty return, try a show parlay. Here's how it works. Everyone in the group antes up $2. In this case, we'll imagine that a group of five starts with $10. Bet the money on a horse to show. Every time you win, bet all the proceeds (minus the spare change) on a horse to show in the next race. In racing lingo, that's known as a parlay. If you can keep the string going for 10 races, the results can be surprising.

The table below shows how the winnings would accumulate if a show parlay lasted for 10 races. To make the math easy, we'll assume that every horse pays $2.80 to show, a reasonable average price. We'll also subtract out spare change that accumulates and add it back at the end. Notice as you follow along that the total amount bet is divide by two in doing the math, since payoffs are always based on a $2 bet.

1. 5 x $2.80 = $14

2. 7 x $2.80 = $19.60

3. 9.5 x $2.80 = $26.60

4. 13 x $2.80 = $36.40

5. 18 x $2.80 = $50.40

6. 25 x $2.80 = $70

7. 35 x $2.80 = $98

8. 49 x $2.80 = $137.20

9. 68.5 x $2.80 = $191.80

10. 95.5 x $2.80 = $267.40

Adding back the $3.40 in change subtracted along the way, the original $10 investment is now worth $270.80. Everyone who put up $2 gets back $54.18. Your parlay, of course, could return more or less depending upon how much the horses you bet pay. And let's face it, hitting 10 races in a row -- even simply picking a horse to finish in the top three -- is a tough assignment. But it's fun, and the worst-case scenario is everyone's out two bucks.