I’m not sure it matters. I figure anyone who memorizes extra digits from the mouseover and then answers based on such recently acquired knowledge is the sort of dastardly scoundrel whose responses can’t be trusted anyway. But since you’re kind enough to offer, I’ll take you up on it should you happen by again. Thanks.
Is done.
When I composed the poll I meant digits overall, e.g. 3.14 = 3 digits. Now I fear my lack of clarity on that point will prevent me from being able to use the results in any peer-reviewed research. Oh, drat! 
Thought I knew 10, though my half-assed guess at #11 was correct (3.141592653 … uh, maybe 5).
I know to 15 digits, 14 behind the decimal point. I answered 13.
Oh, you’re talking base 10?
3.243F6A8885A3[sub]16[/sub], so how many digits is that? B?
3.14. Three numbers, one decimal point. That’s it. Of course, I think all pi should be chocolate.
opps
I know nine, but i get one of them wrong.
qt3.14159!
Damn. I got it wrong. I had a “7” in my head that just ain’t in there:
3.1415972
I put 8, I’m only correct to 6 and only then if no attempted rounding of assumed further values takes place.
Que j’aime à faire apprendre un nombre utile aux sages.
Glorieux Archimède, artiste ingénieux !
Toi, de qui Syracuse, aime encore la gloire,
Soit ton nom conservé par de savants grimoires.
Jadis, mystérieux, un problème existait.
Tout l’admirable procédé, l’oeuvre étonnante !
Que Pythagore découvrit aux anciens Grecs:
Ô quadrature ! Vieux tourment du philosophe !
Sibylline rondeur, trop longtemps vous avez
défié Pythagore et ses imitateurs !
Comment intégrer l’espace plan circulaire ?
Former un triangle auquel il équivaudra ?
Nouvelle invention : Archimède inscrira
Dedans un hexagone ; Appréciera son aire
Fonction du rayon. Pas trop ne s’y tiendra !
Dédoublera chaque élément antérieur ;
Toujours de l’orbe calculée approchera;
Définira limite ; enfin, l’arc, le limiteur
De cet inquiétant cercle, ennemi trop rebelle !
Professeur, enseignez son problème avec zèle…
Not that I remember all that. I know this off the top of my head:
3.14159265
When I do mental arithmetic, I use the trick we had to learn in grade school, pi=22/7
My 9 year old decided to memorize Pi. I have no idea why, I knew it to several digits, but I never told him about it. He’s up to 140. Kicked my ass he did.
Becoming obsessed briefly with The Pi Song doesn’t hurt. 
I can spit out 8 digits, past then I have to think and refresh my memory.
At a high school science supper nerd fest years ago I meet TWO folks who had PI memorized to a hundred places. So, apparently about 1 nerd in 50 knows PI way too well. And a bunch of em knew it way past what you’d ever need practically.
3.14529 for sure
After that, I’m likely misremembering.
<looks a few posts above>
Ok, I’d have remembered the next few right,
So… 3.1452965
I never tried to remember it very far, but I do recall thinking ‘Damn, there’s an awful lot of fives in there’.
Wins my vote for “most accurate version of Pi anyone will ever need in a real-world application”.
I know how to find the pi key on a calculator, which is all anyone ever needs to know.
pi and e to 8 decimal places are stuck in my head like my SSN. I think that memorizing 10 digits is pretty trivial. After all, a phone number has 10 digits, and a full ZIP code has 9 digits. No mnemonic device is really necessary.
I best you at your own game: I decree pi = 3.00000000000000000000 and win by 20 digits, without contradicting precident.