How the Game is played -

A wood-and-chrome, bowl-shaped wheel with blocks numbered 0 to 36 is spun in one direction. (The American wheel has an additional number: the Double-Zero (00), and it can be spun only in one direction, whereas the French wheel can be spun in both directions.) The numbers 1 thru 36 are evenly split between red and black, while 0 and 00 are green pockets. A small ivory ball is spun around the outer rim of the wheel in the opposite direction. As the ball slows, it drops into one of the pockets of the wheel. You bet on which pocket the ball will drop into. There are a large number of bets allowed in casino roulette.

Types of Bets

Inside Bets

Single Bet: Wager on a single number. Place the chip centered on any specific number 1 to 36, 0 or 00. The Payout is 35 to 1. Also called Straight-Up Bet.
Two-Number Bet: Wager on two numbers. Place the chip across any line separating any two numbers. The Payout is 17 to 1. Also called Split Bet.
Three-Number Bet: Wager on three numbers. Place the chip on the line at either end of a row. The payout is 11 to 1. Also called Trio or Street Bet.
Four-Number Bet: Wager on four numbers. Place the chip on the spot where any four numbers meet. The payout is 8 to 1. Also called Four-Spot or Square Bet.
Five-Number Bet: Wager on 0, 00, 1, 2, 3 (Only on American Wheel). Place the chip at the end of the row, on the line where the 0 and 1 come together. The payout is 6 to 1. Also called Five-Spot or Sucker Bet. 

Red / Black: Wager on red / black numbers. The payout is 1 to 1. The only number not red or black is the green 0 or 00.
Even / Odd: Wager on even / odd numbers. The payout is 1 to 1. The only number not even or odd is the 0 or 00.
Column: Wager on one of the three columns of 12 numbers. Place the chip at the end of the layout, in the box marked 2 to 1. The payout is 2 to 1.
Dozen: Wager on a particular group of 12 numbers (1-12, 13-24 or 25-36). Place the chip at the specific wagering box, labeled 1st 12, 2nd 12, and 3rd 12. The payout is 2 to 1.
Low / High Number: Wager on 1-18 or 19-36. Place the chip at the specific wagering box, labeled 1st 12, 2nd 12, and 3rd 12. The payout is 2 to 1.

En Prison

When an 1-to-1 wager is made, and an 0 comes up, your bets are moved to another line and "held enprisoned", waiting for the next spin: If the next spin wins you get your money back, if not not. Not all casinos offer this rule!

Surrender

When an 1-to-1 wager is made, and an 0 or 00 comes up, you lose only half of your bets. Not all casinos offer this rule!

Payouts

The casino has to pay for rent, salaries, free drinks, air conditioning, lights etc. The difference between the payout and true odds is what pays for all those expenses. The trick is to play low odds bets.