In an attempt to preserve the life of text books, most schools require that students cover them. Some schools are requiring students to purchase the stretchable fabric book covers that just slip on, but others will allow students to cover books themselves.
I remember carefully crafting book covers out of brown paper bags, white craft paper and cool gift wrapping scraps. For those of you looking for some step by step directions for making your own book covers, here are two good tutorials:

How to make a paper bag book cover 
Make a paper bag book cover