I do not. There was a pad in the box where my gf’s family had kept score and kept record of high scores. I remember my score was significantly better than any of their high scores.
A second (or third etc) Yahtzee scores 100 point bonus and can be used in 3 of a kind, 4 of a kind, full house, chance, or the upper section. If the appropriate spot in the upper section is already filled, you can also use the second Yahtzee as a wild card as either straight. You only can do this if the first Yahtzee was scored and not zeroed out. We had arguments about how to score a second Yahtzee if you zeroed out Yahtzee then got two of them. The rules we had didn’t cover this.
That is my understanding. For a yahtzee after it has been zeroed out, my understanding is that it can be used as 3 or 4 of a kind, chance or upper section. I just thought of full house. Does it have to be 3 of one number and 2 of a different number?
That seems unneccessarily complicated, and totally skews the competitive balance of the game. If one player gets two yahtzees and the others don’t, they’ve got a big advantage already. The extra 100 point bonus pretty much guarantees the win.
Even if you haven’t used, or zeroed out, the yahtzee square, rolling a yahtzee would qualify as three- or four-of-a-kind. You’d be crazy to score it that way, but it fits the requirements for either of those boxes.
Full-house I’m not sure of.
Interesting. Just from a quick google, this does appear to be somewhat contentious, with some rulebooks saying “three of one kind and two of another” while another one says “any three of a kind and any pair.” See here and see here..
I personally would be inclined to count it as a full house.
I like my rule just for the simplicity of it; a yahtzee can be used to get the maximum score in any box.
I know it’s not technically the same as Yahtzee but Dice with Buddies doesn’t let you use it as a Full House. Ask me how I know this… 
Years ago we changed the rules to our version, in which the second Yahtzee doesn’t get you any bonus points, but must be used only where it fits: 3 of a kind, 4 of a kind, chance, or on top if that number is still open. (I don’t think we allowed it to be a full house.) My house, my rules.
Made for a much more competitive game.
It seems as though it should be possible to program a computer for optimal Yahtzee strategy. Consider the trivial case where it’s the final turn. Knowing which box it has to fill, it would be possible to calculate which dice to keep, and which to re-roll, to get the best score in that box, and what the probablities are of getting different scores.
On the next-to-last turn, after each roll of the dice, it could calculate the best score in either remaining box, and the likely score it would get by leaving the other box blank. What can it score on this turn, plus what it expects to score in the blank boxes which will remain. Optimize for that.
Keep applying that logic and it should be able to caluculate an expected score at each decision point in the game. It would get pretty computationally intense, but it seems doable.
It has been done. I posted the link earlier.
On my own I looked at the strategy for when there was only chance remaining. - After the first roll, keep 5s and 6s. After the second role, keep 4s, 5s and 6s.
I also looked at what to do when there was yahtzee and chance left. When do you go for yahtzee and when do you go for a higher chance? This was all with Expected Value. In a real game it’s unlikely a couple of points would make the difference between winning or losing, but getting a yahtzee makes a major difference.
Oh, I missed that link earlier. Thank you.
I’m a little surprised it runs as quickly as it does. Makes me wonder what programming tricks they use to optimize it.
On Hasbro’s website they have the rules posted and it unambiguously says a Yahtzee can be used as a full house, if you have already rolled out, or have zeroed out the Yahtzee, and can’t use the corresponding upper box score.
Yeah, I just checked a Travel Yahtzee game I have (though it’s branded Milton Bradley), and it explicitly states that a Yahtzee can be used as a wildcard, provided the conditions you stated, for 3-of-a-kind, 4-of-a-kind, full house, small straight, or large straight.
Just to briefly resurrect this; I decided to play many Yahtzee games on IO to see what percentage of the time I could beat the computer, playing what I think is basically sound strategy.
I embarked on playing 162 games (the length of a baseball season, of course) and so far am 67-50.
THE reason I have a winning record is the top bonus. I get it more than half the time; the computer doesn’t make enough effort on it and gets it a quarter of the time.
Out of idle curiosity, are you keeping track of Yahtzee rolls? When I play, it seems that the computer scores a Yahtzee considerably more times than I do.
I am surprised at that the computer’s strategy is to maximise expected score. I am not certain but I would be surprised if it is not completely optimal.
What the computer doesn’t do it try to beat an opponent, if you are aware of the computers score you can take more risks if you are behind and play a little more conservatively if you are ahead. This is especially true if anyone gets a second (or third) Yahtzee and in that case the winner is almost guaranteed to be the one with the most Yatzees.
The IO app keeps track of that for you. We’re dead even.