For a generation of young adults, Reading Rainbow was a PBS staple. Now the show is back in a different form — an app made just for the iPad. The app comes with video segments starring the show’s host, LeVar Burton, going on “video field trips” as well as, of course, access to lots and lots of books — for a fee. The app will give you one book for free, and then requires a subscription of $9.99 per month or $29.99 for six months. This one’s aimed at kids, but in-app purchases are password protected. Children earn virtual stickers for every book read, which can be placed in their own sticker book. The app is built around genre-based “islands” with themes such as “Animal Kingdom” or “Genius Academy” and also includes book-related games. Free to download, for the iPad.