All the things on this board, and if you're at the east end of 30A, go to Villages of South Walton Seacrest Cafe and get Carvel Ice cream and watch the fountain "dance" to music sometime between 8:00 - 9:00 in the evening. People can run through the fountain. Someone on this board can let us know the exact time the fountain dances to music (with lights). It's not Las Vegas style, though, which I like -- more subtle.
We have kids, too, and we like to get take-out from Angelina's (seafood linguini for adults and pizza or something for kids) and then eat at the cottage inside or on the porch to avoid the crowds. Call ahead.
Get skim boards for the kids and remember to get the wax for the boards as well. Keeps the kids close to shore and having fun. You can get the boards at publix and I don't know where you pick up the wax along 30A.
Make "drip" sandcastles:
http://avant-gareth-studios.com/me/sandcastle.html
Have a funn time!