If there's a commotion going on in a physical casino that sounds like a bunch of excited people, it's probably coming from a craps table. The popular dice game is a very social one thanks to the large amounts of money that can be won (and, yes, lost) on a single roll, as well as the fact that most players are betting the same way. That sense of everyone being in it together isn't quite the same in online craps, but it's still a fun game with excellent odds once players get to know the basics.
The craps layout can be a confusing place thanks to the dozens of different wagers it supports. In truth, many of these bets are heavily weighted toward the house, and beginning players can ignore a good portion of them. One nice thing about online craps is the fact that the games generally help players understand exactly what bets are valid ones at any given time. The most basic wager is made on the pass line. Everyone must have a valid pass line bet (or its opposite, the don't pass line) in order to place other bets. An initial or "come out" roll of seven or 11 is an automatic win for pass line bettors, while rolls of 2, 3 or 12 is called craps, making them losers.
Any other roll establishes the point, at which time the object becomes to roll the same number on subsequent rolls. Hitting the point makes all wagers still on the pass line winners, while a seven rolled after a point is established makes them losers. Another common bet that can be placed after the come out roll is a come bet, which automatically moves to other potential point numbers if they come up - for instance, if an eight is rolled while six is the point, the come bet money moves to the eight. All pass line and come bets can be backed up by taking odds, which means placing additional money behind those same bets. Taking odds reduces the house edge to a bare minimum by creating some of the few situations in gambling that pay out at true odds.
Other craps bets mostly focus on specific numbers that might be rolled on the very next roll, and should usually only be placed by players who are already winning money. One other thing to keep in mind is that several wagers might be active at the same time, so players need a larger bankroll to play craps than they would at a blackjack or roulette game with the same betting limits.