One Sheet Pocket Book

You can use any size paper, double sided scrapbook paper is ideal since it has some weight to it.
Just fold, cut, and glue.

Tutorial

Easy One Sheet Minibook with Recycled Covers

Little and easy to make mini book using one sheet of paper for 16 pages (including end papers) and cereal boxes for covers. Binding is a simple stitch, pamphlet stitch. Covers are magazine pages.
If you want more pages, just use extra sheets of paper.
You can also use scrapbook paper, even cutting some scrapbook paper to use as the end pages.
Ribbon or fancy yarn can be used to bind the book.

Tutorial

One Sheet Wonder Mini-Album

One 12 x 12 piece of scrapbook paper, a few cuts, and decorate.
Folds up nicely.

Tutorial Link

View another creation for more ideas

One Sheet Minibook - 12x12

Tim Holtz uses one sheet of double sided 12 x 12 scrapbook patterned paper.
Score, cut, fold!

One Sheet

One sheet, one cut and fold mini-book also know as a "zine" type book.
Can make any size.  Recycle one side printed flyers!

Quick Fold 16 Page Book

Video Tutorial here