Calvinball: The Rules of the Game That Has No Rules

You remember what it was like as a kid: roaming the cul-de-sac, playing games, and heading home only when the streetlights flickered on.

Maybe your games had set rules. Maybe they had a legit scoring system. And maybe they were played the same way every time.

But where’s the fun in that?

That’s the beauty of Calvinball, the eponymous name for both Calvin and Hobbes’ favorite nonsense game that’s never played the same way twice. We were first introduced to it on May 5, 1990. Calvin had just quit the recess baseball team that Moe bullied him into joining. Rather than sulk about the ridiculousness of organized sports, the best friends donned masks and played the most chaotic game they could think of. 

The ease with which they fall into the competition makes us think it’s a long-standing tradition. In fact, some folks reckon Calvinball premiered as far back as this strip on Oct. 26, 1986, though it’s not specifically named. In it, Calvin and Hobbes play what appears to be capture the flag, but Calvin keeps inventing new rules midgame to suit his needs—the essence of what would later become Calvinball: 

In truth, Calvinball was born on the fly, just like the rules themselves—which, by the way, don’t exist. Or, more accurately, “The only permanent rule in Calvinball is that you can’t play it the same way twice!” Calvin announced in the May 27, 1990, strip. 

Over the years, subsequent arcs involving the game prove that out. Most games do involve a ball, naturally, but whether it's a soccer ball or volleyball seems dependent on what’s on hand. Masks are must-haves, but equipment varies between pickets, flags, or “time-fracture wickets.” Rosalyn, the babysitter, even makes use of a “babysitter flag,” which seems to be the only instance of Calvin heeding her authority and going to bed when told. Scoring is wonderfully random: In the game above, for example, the score was Q to 12, and in another, the score was oogy to boogy.

Calvin sums up the ethos of Calvinball in his official song (which he of course made up spontaneously; very on brand). He belts it out during the Rosalyn/Calvinball arc from Sept. 4 through 16, 1995: 

Other kids' games are all such a bore!
They've gotta have rules and they gotta keep score!
Calvinball is better by far!
It's never the same! It's always bizarre!
You don't need a team or a referee!
You know that it's great, 'cause it's named after me!
If you wanna have fun!
Play Calvinball!
da da buh dum!

Later that month, we saw the final Calvinball match, just weeks before the strip officially ended. Calvin reminds us that “Sooner or later, all our games turn into Calvinball.”

Today Calvinball is still very much in our lexicon, and not just with “Calvin and Hobbes” stans. In March 2025 it was added to the Oxford English Dictionary, with this definition: “Activity reminiscent of the imaginary game of Calvinball ... in not following any discernible rules, or in which individuals act in a self-servingly inconsistent manner.”

It’s popped up in some surprising places too: Justice Ketanji Brown Jackson referenced Calvinball in her dissenting opinion in National Institutes of Health v. American Public Health Association this month, calling out “Calvinball jurisprudence” to describe shifting rules. 

That’s the magic of this game—it isn’t really about sports at all, organized or otherwise. It’s about the joy of imagination and making up the rules as you go. In the end, if you’re playing Calvinball, you’re already doing it right.