PDFSpinner randomly selects a PDF from a specified folder and displays it for you. You can request another PDF, and another will be randomly chosen. PDFSpinner maintains a list of displayed PDFs and ensures that they are not repeated until all have been displayed. I use it for guitar chords and songs, but you may have another use where you want a random PDF. One of my testers told me that with the new features in 2.0, particularly Search and Table of Contents, PDFSpinner makes a pretty good songbook. Give it a try!