Tonight at sundown are fireworks in Astoria Park (viewable from the big lawn). Bring your friends, a blanket, some snacks, and enjoy the show!
Afterwards, continue the celebration at a number of places nearby - on 24th Ave, the Beer Garden, of course, will be rockin' with the crowds, probably with a long entry line to boot. Across the street is my beloved Sparrow, where where you can get some delicious food and drink. 24 (25-19 24th Ave) up the street is a good bet, too. And up on 31st Street is Balkh Shish Kabab (open til midnight), which is worth trying. No alcohol served but tasty food is. They have interesting wall hangings, too - keep an eye out. 23-10 31st St.
On Ditmars, you've got Waltz Astoria (23-14 Ditmars Blvd, open till 11pm) where you can satisfy your sweet tooth, Crescent and Vine (25-01 Ditmars Blvd) for some wine and nibbles, and Fatty's right next door (love their burgers and sweet potato fries).
In any case, enjoy yourselves tonight!