As for languages, this could be the time to get out those books and tapes that we didn't have time to really sink into the year before. Arouse their natural curiosity. Even if the children don't understand one single word of the new language yet, and declare they have no interest in learning it ever, they'll pick up something from the songs. Before you know it, they'll want to know what a particular song in this foreign language means - especially if it has a catchy beat. Summertime is the perfect time for easing into it.
Sign language is another option.
The basics of sign language are easy to learn by starting with the alphabet. A trip to the library can glean information about the origins of the language, the life stories of Helen Keller , or Louis Braille and his alphabet for the blind. Yes, the children will have fun. More importantly, they will be learning about the indefatigable human spirit and the challenges others have faced and surmounted.