Design Improvised shares a post about putting together a summer picnic for kids that has a lot of great ideas. One of my favorites is this string-a-treat necklace that kids will love making as much as they'll love eating. Keep this in mind for car trips and party activities too.
Lost Button Studio shares this wonderful selection of games all stored in a jar that makes it easy for traveling or gifting. There's even a free printable for the game instructions!
This is one of the coolest things I've seen in awhile! BhoomPlay shows you how to make this fascinating jellyfish in a bottle using a plastic bag. I think this would be a great party favor for a an ocean-themed party!