We went to a free concert in the park last night, and the kids were blown away by the fireworks afterward. My son kept breaking out in spontaneous applause and even gave the fireworks a standing ovation at one point! Never seen him so excited - that was nice.
My daughter liked the fireworks display and pointed out when they were her favorite colors (pink and purple) but wasn't as completely blown away. Maybe next year (she's 3 1/2 now).
How do your kids like fireworks?