Double flop Hold'Em poker is a variation of Texas Hold'em where you deal out two separate boards or community cards. Each player is still dealt out two hold cards to make their hands, but they will get to make two seperate hands to play, one for each set of community cards.
To play, deal each player their two cards, bet, then deal out two flops. Another round of betting, then deal two turn cards. Bet, then deal two river cards. In the end, you should have ten cards face-up in two rows of five. Now each player makes his/her best hand for each row and the pot is split between the winning hand for each board. It is possible for one person to win both hands and scoop the whole pot, too.