Back in the early 90's I used 3 by 5 card to keep my to do lists. Well, it seems like the 3 by 5 card is making a comeback. From 43folders.com comes the "hipster PDA" which is described as:
A "Hipster PDA (Parietal Disgorgement Aid) is a fully extensible system for coordinating incoming and outgoing data for any aspect of your life and work. " It helps you assemble one in this way:
Building your first Hipster PDAhere for more information.