As we approach the end of May, a lot of people are looking ahead to their summer vacation. If you're planning to visit a national park, you'll want to download Chimani National Parks (free), which has information and news about the nation's 394 National Parks System locations. The app includes details on all national parks, monuments, memorials, seashores, recreational areas, sites, battlefields, historical parks, and parkways. It also gives you access to the news provided by the National Park Traveler website. A main feature of the app is the "virtual passport," which lets you "stamp" the parks that you've visited. The app also includes interactive maps.