Any quiz that invokes a challenge to the reader.

Aim TestHand Eye Coordination Test - How Good Is Your Hand-Eye Coordination?Spacebar Test - Check out how fast can you press the spacebarHearing Test Online - How Old is Your Hearing?Kohi Click TestJitter Click TestNumber Memory TestReaction Time TestPass this test, or stay forever alone!Speed Reading TestTyping Test - Check your typing speed in 60 seconds, instant results!Comprehensive Knowledge Radar TestCPS Test / CPS Tester - Check Your CPS with Clicks Tracking ChartColor Hue TestCan You Distinguish Between Asian Faces?APM Test - What is your APM? (Actions Per Minute Speed Test)Test Your Level in GeometryShort-Term Memory TestHow Good Is Your Memory?Color Blind Test (Color Vision Test)Visual-Spatial Reasoning TestHow Sensitive Are You To Colors?Can You Spot What Is Hidden In These Pictures?LOL Audio Challenge Test