Pascal's Wager is a very classic and widely used argument by both professional apologists and layman. It is based on 2 premises. You lose nothing by believing but risk losing everything by disbelieving.
1: Belief in a god costs you time and restricts your actions.
2: There are currently 41,000 active denominations of Christianity alone; most of these are exclusive. There are an additional 37,000 other active beliefs. There are also estimated to be over 70,000 extinct religions. This means that picking a religion at random would give you a 1/148,000 chance of being correct. That means choosing a religion at random would give you about a 99.9993% chance of being wrong.
3: It is possible that none of the religions today are correct. So by choosing a religion today you are suffering the consequences with no chance of reward.
4: It is possible that god would punish those who hold unwarranted beliefs.
5: There is no more evidence for god existing than there are leprechauns. Suggesting that you should act based on this is akin to suggesting you should chase the end of rainbows as there might be a pot of gold at the end.
We know we are alive today. We do not have any reason to believe that a god exists or that there is a punishment waiting for us for disbelieving. Even if you assume god does exist and some one has actually discovered the correct belief system, you are sacrificing the quality of life that we have now for a 0.0006% chance of being correct. The best case scenario is not much better than playing the lotto but rather than spending $3 for a ticket, you are altering your entire life style and beliefs.
Finally, being a believer of any particular faith or an atheist would place you in the exact same position under the logic of pascal's wager. Believers could choose the wrong belief, be punished for believing, or happen to be rewarded for their belief. An atheist could be punished for their disbelief or happen to be rewarded for their belief. So in the end, it is more rational to go with the stance that has no cost to the life that we know we have. It is only rational to disbelieve.