hey, you built a football quiz - that's pretty cool. to get people to play, hit up where the football fans hang out online. think reddit, facebook groups, twitter.
share it not just as a link, but maybe post a tough question and challenge people to answer.
keep it fun, like a mini-game. no cash for ads? no sweat. word of mouth is your best friend. and those leaderboards and friend challenges you're thinking about? do 'em. it's the stuff that'll make folks come back and bring their pals. good luck, and keep at it!