Index Card Organizer

I have found that index cards or 3x5 cards are great for keeping notes during meetings or creating reference cards for anything you might need a quick refresher (e.g., application shortcuts, command-line arguments, etc.)

I printed this organizer that has 8 slots to organize my cards into different categories/projects. The print has butterfly-style joints underneath to allow multiple ones to be snapped to each other, although I haven't printed the joins yet.