I have been coming to the DE beaches my entire life. As a kid, we went to my grandparents' beach house in Lewes...and now with a 2 and 4 year old, myself, we return nearly every weekend to my in-law's beach house. We take daily bike rides (have you tried the Breakwater Trail or the bike path around the Villages of Five Points?), hit up the pool, and of course truck a cartful of stuff to the beach.
Despite returning every one of my 32 years, I still manage to find new kids activities at the Delaware beaches each time I return. When we come down for week long stretches, it's nice to find beach and boardwalk-alternatives, especially for the really hot, rainy, or really crowded weekend days.
Funland at the Rehoboth Boardwalk, Jungle Jim's and the other water parks, outlet shopping, and the beach are the obvious kid-friendly activities. But aside from the biggies, there are some real hidden gems (many of them free). Lucky you - now I'm letting you in on my little secret so you and your kids can get even more out of the DE beaches. Free events are indicated with an "*"