The rolodex project is taking a vintage rolodex and creating a scrollable idea, inspiration or instruction collection of notes. It could also include passwords or some other bits of information. There could also be an entire rolodex devoted to the bible, or one devoted to creative brainstorming and mood selection. The analog vs digital format and the act of scrolling through a real object with your hands means an experience in the world different in your brain from just using webpages or other computer on-screen tools.
Sometimes called a memory dex, people have created very ornamental rolodex cards.
People have complained that some of the modern products aren't as of high quality as the older rolodex units. Plastic can fatigues so there's a risk getting an old one too.