iA Writer - Minimal Design, Maximum Focus
QuizUp - QuizUp gives you the opportunity to test your trivia skills against friends and strangers throughout the world.
MacDown - MacDown is an open source Markdown editor for OS X, released under the MIT License.
A Google a Day - Online trivia game where you use Google's search to answer questions as fast as you can.
MWeb - Pro Markdown writing, note taking and static blog generator
Trivia Crack Kingdoms - The amazing quiz game that lets you test your knowledge and challenge your friends to see who is the smartest. Developed by Etermax