Remember when Biff Tannen travelled back to 1955 and gave his younger self the 2015 Sports Almanac? Ok, SportCrypt is only tangentially like that, in that it involves sports betting. It's a decentralized, P2P sports betting app. It won't predict outcomes, but it can offer the next best thing: in-play betting, a.k.a. betting on ongoing events. You can place a bet, cash out of a bet, or trade positions, up until the game ends. That's almost better than a DeLorean, if you ask me.
SportCrypt represent certain advantages over regular sports betting. There's no counter-party risk (danger of someone stealing your money) because your funds are held in an open source smart contract. There's no painful international payment processes and conversions, because we're dealing with internet money (a.k.a. ETH). And the game is entirely zero-sum between players, meaning the app takes no commission (there's always gas though!).
To play, go to My Account and deposit funds through MetaMask. Then browse betting offers. You'll find bets on MLB, soccer, MMA, WNBA, and more. These options aren't the limit though; this is P2P, so if your favorite sport is hackey sacks or head-tennis, just post your own offer!
On SportCrypt you play for fixed-odds, because this is for civilized gamblers, not those savages that play parimutuel betting at the horse races. Fixed-odds means final payout is agreed at the time the bet is sold, whereas with parimutuel betting you won't know your payout until the bet is closed. Basically, on SportCrypt you know your odds before you place the bet.
And now for the spice we mentioned earlier. Normally in betting, you can only bet up until an event begins. But on SportCrypt, you can bet on ongoing events, or cash out of ongoing bets, up until the last second of a match. Say you bet on Brazil and Neymar sprains his ankle in the first half. You could actually cash out immediately, and bet on the opposite team!
For the full technical details on betting, we strongly recommend you check out the SportCrypt whitepaper. Betting during a match is risky because everybody will be trying to trade positions to reflect whatever's happening on the field, and conflicting transaction on the network can go either way. If leave during-the-game trading to the pros.