I love to participate in different contests/challenge on Hive blockchain.
Here I am trying summaries some of them and they worth to give a try.
Daily Alive Engagement Contest - Win 200 Hive Power Every Day initiative by @nelinoeva
Weekly Challenge by @SPLINTERLANDS
Weekly Question initiative by @ecotrain
Daily Contest Math Brain Teasers by @gungunkrishu
Daily MONOMAD Contest initiative by @monochromes
Daily COMMENT and SPORTS initiative by @amr008