Akiyoshi's Illusion Pages
A professor's personal gallery of illusions he actually designed and researches.
Akiyoshi Kitaoka is a psychology professor at Ritsumeikan University who creates and studies visual illusions professionally — this is his personal page collecting them, including some (like the rotating-snakes illusion) that have gone properly viral. Free, static, no ads, exactly as unpolished as an academic's personal site should be.