I didn't know the origin before - as in why May 25th - but the Wikipedia article provided the background, and even the original proposal via Web Archive: https:

I didn't know the origin before - as in why May 25th - but the Wikipedia article provided the background, and even the original proposal via Web Archive: https://web.archive.org/web/20020424065309/http://systemtoolbox.com/bfarticle.php?content_id=46 https://web.archive.org/web/20020424065309/http://systemtool... Edit: To save the unknowing a link click, May 25th was two weeks after Douglas Adams' passing.