Over at Finer Things, David Chartier points out that Siri can help you play games of chance. Unfortunately, however, the virtual assistant can't necessarily help you win at said games. Still, you can use Siri when you need to flip a coin or roll a pair of dice.
Say "Flip a coin," and Siri will either announce that it's heads or tails. Ask Siri to "roll the dice," and you'll get a pair of numbers between one and six. You can't ask Siri to roll a single die. Or rather, you can, but you'll still get two numbers back.
Hardcore role playing game enthusiasts will need a separate app or actual dice hardware to roll dice with more than six sides; Siri's apparently not into D&D.
Mac OS X Hints