Starting at 10 am, there's a bike tour and a scavenger hunt at Tubman field, plus yoga at the same time (from NCH advertiser Quiet Mind Yoga!) There's also a dog show, tons of live music (Irish, reggae, rock, Latin, hip hop and more), a King and Queen of Columbia Heights contest, and the popular (and hilarious) cupcake eating contest.
There's also going to be a lot of booths with local organizations, businesses, politicians, craftspeople, and more. The DC State Fair will be there too with a pie baking contest and other fair-related events. I'm guessing local establishments will have deals too; they did that last year.
It should be a great time, and I hope lots of folks come out. The full schedule is on their site.