I'm particularly interested in differences - small or large - that you didn't realize for a long time, automatically assuming that everyone was like you in that regard. It can even be something as trivial as always having conceptualized the passing of years as a visual timeline, and then finding out that not everyone does so. I'm also interested in links to blog posts where people talk about their own mental peculiarities, even if you didn't write them yourself. Also books and academic articles that you might think could be relevant.
Some of the content that I'm thinking about including are cultural differences in various things as recounted in the WEIRD article, differences in sexual and romantic orientation (such as mono/poly), differences in the ability to recover from setbacks, extroversion vs. introversion in terms of gaining/losing energy from social activity, differences in visualization ability, various cognitive differences ranging from autism to synesthesia to an inability to hear music in particular, differences in moral intuitions, differences in the way people think (visual vs. verbal vs. conceptual vs. something that I'm not aware of yet), differences in thinking styles (social/rational, reflectivity vs. impulsiveness) and various odd brain damage cases.
If you find this project interesting, consider spreading the link to this post or resharing my Google Plus update about it. Also, if you don't want to reply in public, feel free to send me a private message or an e-mail ( firstname.lastname@example.org ).