Find a book you want to borrow. A good site to use is archive.org
Download Epubee's Epub DRM Removal software at this link HERE.
Once your book(s) have been loaded in ADE, open up the DRM removal program.
You will be presented with a prompt. Select load from C:/Users/USERNAME/Documents/My Digital Editions, if it isn't already selected.
Within a few seconds, it will have the books decrypted. Move the books from ADE in the Documents folder elsewhere.
Congratulations! You just... "technically"... stole a book. ADE will return the original copy back to the library, but you get to keep your own copy. So, technically, it's not stealing, really, it's just pirating in a way.