Not sure what to play?
Pick a vibe or category. Roll. Re-roll until something clicks.
Rolling for: 🎲 Random
Free Game Tools
No signup. Use them mid-game on any device.
Settle It Instantly
Real rule disputes — answered with official sources.
“What are the players & officials in Sport Sambo?”
The FIAS Regulations on SAMBO Referees were likewise amended by the Executive Committee on March 31, 2026. FIAS descr...
“What is setup in Mahjong (Riichi)?”
Four players, each associated with a seat wind. East is the starting player; South sits at East's right, West across ...
“What are match formats in Capture the Flag?”
Single round: First capture wins the match.; Best of 3: First team to win 2 rounds wins the match. Teams switch sides...
“What is extras — law 24 (byes), law 23 (leg byes), law 22 (no ball), law 22 (wide) in Cricket?”
Extras are runs added to the batting side's total that are not credited to any individual batsman's personal score: B...
Hot Rules Right Now
Most-viewed official rulebooks this week
Featured Sports
See all →Fall Sports
Fall-season competitive sports
Did You Know?
10-Point Must System
Same rule. Different sports. Different answers.
IBF
All IBF championship bouts are scored using the 10-point must scoring system. Under this system, the winner of each round receives 10 points, and the loser receives 9 points or fewer.
PowerSlap
Matches are scored on the 10-Point Must System. Open scoring may be used at the Promoter's election, in consultation with the Executive Director and/or Commission.
Gaining Traction
Community sports picking up momentum right now
Recently Updated Rules
Official rulebooks with fresh changes
GAA
3 rules updated · yesterday
Latest: Section 6: Scoring
WCT
6 rules updated · 6d ago
Latest: Section 8: Safety Considerations
ISU
29 rules updated · 8d ago
Latest: 8.4 Heat Size Limits
International Padel Federation
4 rules updated · 8d ago
Latest: Net and Wall Violations
World Aquatics
9 rules updated · 8d ago
Latest: Section 8: Safety Considerations
World Lacrosse
9 rules updated · 8d ago
Latest: Section 8: Safety Considerations
No More Arguing
Search the Rule
“Is a double dribble legal?” “Can you bounce in beer pong?”
Get the Verdict
Cited rule number and source. No opinions — just the answer.
Send the Proof
Share a direct link. One tap — argument over.
No more guessing. No more debates.
Every official sport started somewhere
How a Sport Becomes Official
Open Source Sports gives new sports a visible path forward.
Most sports never reach this stage. Yours can.
This is the path every custom sport follows on Open Source Sports.
What are you here for?
Two tracks, one platform. Pick your path.
Official Sports
Trusted rules from real governing bodies.
- ✓ Verified rulebooks, cited with rule numbers
- ✓ League comparisons and seasonal updates
- ✓ Instant verdicts for common disputes
NFL, FIFA, NBA, UFC, and 209 more
Settle a RuleCustom Sports
Turn your idea into a recognized sport.
- ✓ Create your own sport from scratch
- ✓ Community voting and rule proposals
- ✓ Path to endorsement and official status
Beer pong, backyard games, and your next idea
Create a SportSport of the Day
FIS
Ski Jumping
Ski jumping is one of the original Winter Olympic disciplines, contested at every Winter Games since the inaugural 1924 Chamonix Olympics (men). Women's ski jumping was added at the 2014 Sochi Games after decades of campaigning. The sport is governed by the International Ski and Snowboard Federat...
Explore by Category
Who Decides the Rules
Sourced from 109 governing bodies worldwide.
Help Keep the Rulebook Open
OpenSourceSports stays useful when people improve the rules, suggest missing sports, and support the tools that keep play moving.




