[Download the free books and take them along in one of the new E-Readers.]
Mapping the sky. A smart phone can bring life to a summer sky, with its combination of GPS and motion sensors pinpointing the location of stars and planets in the heavens above. Just point the phone toward a section of the sky and free or cheap software can point out constellations, planets, stars, and galaxies. Google offers the free SkyMap app (www.google.com/sky/skymap) for Android phones. Owners of iPhones and the iPod Touch can get more feature-rich software from Pocket Universe or Star Walk, which each cost $3 at Apple's App Store.
For the birds. Who knew the beautiful cardinal had so many songs and chirps in its little beak, or how its accent changes in different parts of the country? The Macaulay Library (macaulaylibrary.org) at Cornell University has a collection of thousands of wildlife video and audio files that are worth hours of browsing. Birds, mostly North American, dominate the collection with a couple hundred recordings of the Northern Cardinal alone. But it also includes a broad sweep of animals on land and in water. The files are organized by breed, location, and description and a search bar makes it easy to find a specific species.
Image hopping. Yet another offering from the search company, Google Image Swirl (image-swirl.googlelabs.com) encourages free-form exploration of photos, paintings, and illustrations available on the Web. A search for "dinosaur" leads to collections of representations of stegosauri, ankylosaurs, or everyone's favorite, Tyrannosaurus rex. The images can be serious academic renderings or goofy clip art, but they're fun to follow as the service groups them with links to what Google has guessed are related images. Artists get good representation, with Google bots curating the Web's collection of Warhol, da Vinci,and paintings from the impressionists.
Silly and safe. Thousands of hours of cartoons, including classic Popeye the Sailor Man and Tom and Jerry episodes well-known to parents, are available for free from the Internet Archive (www.archive.org). The collection also includes more than a million books and other texts, but the archive is unique for its vintage television and radio shows, foreign language and experimental movies, and live concert recordings. They can be enjoyed online or downloaded in a wide number of formats for carrying along for those long vacation drives.
Cave art. The ancient cave paintings of Lascaux, France, come alive in a beautiful Web tour (www.lascaux.culture.fr) of the Paleolithic-era art. The interactive, 3D site wanders through high-resolution reproductions that are easy to explore, even for those who don't speak or read the site's French-language descriptions. Young visitors might be inspired to recreate just a few of the huge trove of images created by the pre-history painters, including the deer, bison, and horses that were so crucial to their culture of 17,000 years ago.