The idea of this is that you choose five books with your child and read the same five books together each day for a whole week. We are currently doing this with the library books we chose a couple of weeks back. We intend to take these books back next week and then we'll start again with some new ones. This is a fantastic idea. I've observed that if you do this children become so familiar with the books they can 'read' them on their own using the pictures as prompts. It's a real boost to their early literacy skills. It's also a wonderful way of spending time with your child.
Take a look at Anna's post on this for more information, choose some books and get reading! http://www.theimaginationtree.com/search/label/5-A-Day-Books