Sans Forgetica is a free-to-download font that supposedly helps you “remember your study notes”, designed by typographer Stephen Banham and the Royal Melbourne Institute of Technology’s Behavioural Business Lab. It’s a remakably hostile mindhack: the letterforms are designed to be difficult to read without losing their legibility, thereby “prompting your brain to engage in deeper processing” and “question the gestalt understanding of type”.
Millitext is a “font” whose glyphs are just one pixel wide. But it’s really a clever exploitation of how subpixels — the individual red, green and blue lights of an LCD display — are triggered by pixels of certain colors. For example, a magenta pixel triggers the red and blue subpixels, leaving the green one dark between them.
Both via Boing Boing: