I came across this link advertising national Smithsonian magazine Day. it seems that on Saturday September 26, 2009, 800 museums across the country will honor the magzine with an addmission free day for anyone. Sounds like a good family trip day. and free.
Read this, and then click on the blue link of DOWNLOAD AND PRINT ADMISSION CARD. you can print a card on a tab on that page, and then click on the find venues, to select Delaware, and then scroll around the area, several states, and see links to participating museums.
It’s free.
Like, I didn’t know there is a Treasures of the Sea, wreck of the Atocha , little museum in Georgetown, De.?
Might find one you like to visit.
And of course some of the Smithsonians in DC. I guess all of them. I didn’t check. all would be cool. but I bet it will be crowded. Still, it’s Free!