I have been a huge fan of the Scratch programming language for years. I use it to teach a programming unit with my fifth graders every year, and they have a wonderful time learning to code. Scratch was created by the Lifelong Kindergarten Group at MIT as a way to make programming accessible to young children. It has a colorful, intuitive drag-and-drop interface that my students easily pick up with minimal instruction. After a few days of instruction, my students are busy creating their own games and animations. Many continue to use it at home, and over the years I have had students as young as first grade tell me that with older sibling has been teaching them to use Scratch.
Scratch has a wonderful collection of resources, including ScratchED specifically for educators using Scratch. Recently, I discovered that there was a book published for kids (and adults, too!) that used a comic book format to introduce students to Scratch and programming. Super Scratch Programming Adventure is a wonderful resource for this program. It starts out by explaining the basics of Scratch and its interface, and then walks the reader through building basic programs that slowly increase in complexity. All of this is done as part of an ongoing story – readers are building the programs in the book to help the main characters continue their adventure. The book comes in both physical and e-book format, and for a few extra dollars you can get both as a combo pack. If you are interested in using Scratch with your students (or even for yourself!) I highly recommend this book.