Summer's a time of competing smugness: you're certain everyone who's getting married is doomed to divorce, and they're certain you'll pick the cheapest gift in the registry. The latter's a lock, but the former's ripe for action, at WeddingBetting.com
From the guy behind Overheard in New York, WB's a delightfully despicable site that lets you predict the nuptial success of unsuspecting lovebirds based entirely on submitted couple photos (a Hot or Not for judging eternal bliss). Predicting's highly scientific: simply peep the pic and read a brief description ("together since 17", "Russ is a management consultant"), then select whether they'll last "barely past the altar", 1-15 years, or "live happily ever after" -- which they'd better, if they're going to selfishly commandeer Labor Day weekend. After you weigh in, WB displays crowd-sourced probabilities (number of voters, average no. of years 'til predicted split), then displays a photo of another couple, compelling you to judge again, and again, and again, until you turn off your computer and buy a cat
WB also lets you submit couples for judgment, and even link to their wedding site/announcement; throw your holy union up there, and shock everyone by outlasting the naysayers' prognostications. After that, it's Easy Street, because you'll be rolling in fidelity.