Kudos to Boing Boing, which this week is celebrating 20 years on the internet. I have been harvesting material from them for about 12 years; they offer a rich source of eclectic information, informed opinions, and incisive comments from their readers. Two posts this week are of particular note:
I had to look up the word for the title. I was expecting to have to say "double-decennial", but it turns out there is a word for every twenty years: "vicennial" is from the Latin vicesimus+annus. One could also use "vigintennial", but vice is nice.
Other anniversary terms.
You learn something every day.