Six-Seven

From BoardGameGeek:

6-7 is the game explained in 67 seconds. All players flip cards while saying "six... seven... six... seven..." nonstop, in fast 6-7 minute rounds full of pace and confusion. When a pair of 6s and 7s with the same background appears, the first person to spot it and shout it out... wins the round! Plus, a pair of special cards and a surprise rule make it 67% more fun.