mildly related: when i want a single bit of entropy in my day-to-day without fooling myself, i think of a random long-ish word and decide based on the evenness of the number of letters. probably this isn't an unbiased oracle, but it's good enough when i don't have a coin handy and care about avoiding self-delusion more than fair odds.

It’s slightly biased. ( P(even) = 0.5702; Bias = +0.0702 (about 7 percentage points toward heads) ). You can use this Claude Code prompt to determine how much:

Use your web search tool call. Fetch a list of English words and find their incident frequency in common text (as a proxy for likelihood of someone knowing or thinking of the word on the fly). Take all words 10 characters or longer. Consider their parity (even number of letters or odd). What is the likelihood a coin comes up heads if and only if a word is even when sampled by incidence rate? You can compute this by grouping even and odd words, and summing up their respective incident rates in numerator and denominator. Report back how biased away this is from 0.5. Then do the same for words at least 9 characters to avoid “even start bias” given slight Zipf distribution statistics by word length. Average the two for a “fair sample” of the bias. Then run a bootstrap estimator with random choice of “at least N chars” (8 <= N <= 15) and random subsets of the dictionary (say 50% of words or whatever makes statistical sense). Report back the estimate of the bias with confidence interval (multiple bootstrap methods). How biased is this method from exactly random bits (0.5 prob heads/tails) at various confidence intervals?

good one, though it has to be a fairly long word. Personally I check the current minutes of the hour :P