Correct, avoiding same year events. Also, excluding events that has been used in the past. Anything specific details you are wondering about?

Yes, I'm the author and this is a hobby project of mine. The events are both gathered and "verified" with AI every day. I have tried to come up with a large variety of categories, aiming to make it both interesting, challenging and fun for people from all over the world. But the span of categories could definitely be improved. I had a couple of iterations on both the points system and the layout a few months ago, and felt satisfied with it. Thanks for the suggestion, I will definitely take it into consideration for further work on the site.

I saw that it also made its way onto Metafilter - did you by any chance have anything to do with that?