This operates on a "hardware platform" involving 3x5 index cards, a paper clip, and a pen. Sometimes, one might use fairly sophisticated graphical templates to print onto index cards...
Hipster PDA Templates
Obvious Diversion - Hipster PDA Template for Apple Pages
iPhone Hipster PDA Templates (looks like iPhone UI)
D*I*Y Planner | Paper, productivity & passion
PocketMod: The Free Disposable Personal Organizer
iLegal Paper Wallet
PDF Template Generator for Paper Wallet
If this was useful, let others know by an Affero rating