1. roll a 6 sided dice 99 times.
2. write down each result, writing a "0" for every 6 that comes up.
3. take this long string of numbers from 0-5 and convert it from base 6 to base 10.
a. This means starting from the first non-zero digit on the left, multiply it by 6 then add it to the next digit, then multiply by 6 then add to the next digit... etc. until you get a long number with digits from 0-9.
4. Now you will have to calculate the public key. This is more easily done if the private key (the long number you made) is in binary form (1 or 0) so convert the number to binary.
Wouldn't it be more efficient to just use 10 sided dice? This way you can skip some conversions?
or even more crazy, just take $10 in pennies, shake them in a bucket, dump them out and line them up. Not sure how many bits you would need, so I just guessed $10 would be enough (1000 pennies).
So, there would be a way to create a private key without doing any math and just entering 1's and 0's for heads and tails.
Now, this is what we need:
Starting with a bucket of dumped out spread out pennies (so none are overlapping), take a picture, have some software to recognize heads and tails, and convert the result to binary. Though perhaps just looking a the bits in an sha of an image from a lava lamp would be sufficient.