1,757 arenas · one profile · one impact ledger

Play a round. Finish a mission. Count what changed.

iChallenge is a network of 1,757 free challenge arenas, from code to climate to fitness. Five questions a day, a streak that follows you everywhere, and missions whose results are counted on a public ledger, with the math shown.

Arenas live, 14 days1,403
Players7,097
Mission actions logged2
kg CO₂e avoided0.4
Today's 3 challenges

How many colored stickers are on a standard 3x3x3 puzzle cube?

Confident man posing in studio holding a shiny trophy, showing pride in accomplishment.
Photo: RDNE Stock project / Pexels
Daily #34Resets at midnight UTC

Today's round

  • 5 questions
  • 20s each
  • 0 played today

One ranked attempt per day. Practice as much as you like.

Climate, ocean & nature arenas

The flagship cluster. Every mission here logs a real number, from kg CO₂e to litres of water to trees, counted toward SavingTheWorld.org. Network ledger →

Arenas to play now

Every arena has its own daily round and leaderboard. Your level and streak count on all of them.

The tools behind the missions

Alerts become missions, missions become numbers, numbers become impact. These are the working products that make that loop real.

The directory

1,757 challenge and contest arenas, 1,403 live in the last two weeks, 1,509 with a hand-written pack. Each one is its own venture with an agent card other software can read.

Browse by topic

Leaderboard

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How it works

  1. Play the daily roundFive questions, easy to hard, 20 seconds each. Speed and combos add points.
  2. Keep your streakPlay any arena each day. Every 7 days earns a freeze that covers a missed day.
  3. Finish a missionCheck in on a streak or post proof. Missions with an impact unit log a counted result on the ledger.
  4. Climb your leagueEach Monday the top 20% of your league move up. Sponsors fund prizes on the missions that matter.

Badges

Sixteen to collect across the network.

First RoundFinish your first daily round.
FlawlessAnswer every question in a round correctly.
LightningA perfect round in under 25 seconds.
On a RollPlay 3 days in a row.
Week WarriorPlay 7 days in a row.
UnbreakablePlay 30 days in a row.
ExplorerPlay daily rounds in 5 different arenas.
GlobetrotterPlay daily rounds in 25 different arenas.
PolymathPlay daily rounds in 5 different topics.
In the ArenaJoin your first challenge.
FinisherComplete a challenge.
RecruiterInvite a friend who finishes a round.
CaptainInvite 5 friends who finish a round.
PodiumFinish a day in an arena's top 3.
ChallengerReach level 10.
Profile SavedSave your progress with an email.

Save your progress

Add your email to keep your level, streak and badges if you switch devices, and carry them to every iChallenge arena. One email when you save; no spam.