Post-It note, but no one's ever really managed to improve on the basic design -- which might be why MIT's "Quickies" concept doesn't even try. The electronic note system is instead based around a digital pen and special pad, which saves your notes as you jot them down on RFID-embedded Post-Its. Software on your PC then does some quick OCR and, according to the inventors, "uses its understanding of the user's intentions, content, and the context of the notes to provide the user with reminders, alerts, messages, and just-in-time information." Since the database can also store location information, sticking the note on a book or other object allows you to locate it later using the RFID tag, and you can even have notes SMS'd to their recipients. Pretty wild -- but we're more impressed someone finally found a good use for all those digital pens out there. Check a video of the system in action after the break.