UXTesting - Discover how your mobile users feel
unwelch - Web app for friendly betting
Startup Timelines - How the frontpages of famous startups changed over time
Finger Tap Challenge - Finger Tap Challenge is a simple challenge game that involves two players who will have to tap on the screen as fast as they can to win the challenge from the opponent.
Laws of UX - Key maxims that designers must consider when building UX
Spinnner - Challenge your friends to a spin-off (literally)