It's a dying holiday, I'm sorry to say -- I completely forgot it last year. But I was reminded this year, so I'll mention it again. I think the proper way to celebrate it is simply to laugh at a creationist today.
The source of the holiday is a remarkable exhibition from Paul Nelson, who like several other creationists, loves to register and present at legitimate science conferences. The barriers are low, and many conferences are intended to give students an opportunity to present, so you'll often find that all you have to do is send in a fee and an abstract and you'll be allowed to put up a poster in an allotted space for a few hours of time. So Nelson showed up at the Developmental Biology meetings in 2004 with a poster titled "Understanding the Cambrian Explosion by Estimating Ontogenetic Depth" in which he and Marcus Ross claimed to have been collecting data measuring some parameter called "ontogenetic depth" in various organisms.
I was at that meeting. I asked him about that in person, and also in blog posts afterwards. How do you measure ontogenetic depth? Share your procedure so I can assess and replicate it, which is what scientists are supposed to do. He hemmed and hawed and hmmphed and in typical Nelsonian fashion babbled and burbled on, and the upshot was that he couldn't tell me just then, but he had something he was writing and he'd polish it up and get it to me the next day, 7 April. He didn't. We've been watching the 7th of April pass by for nine years now.
I think he's felt the sting of mockery. In 2010 he announced that my criticisms were invalid, but he was inventing Ontogenetic Depth 2.0, which still isn't defined and still doesn't have a procedure.
In 2011 he posted some more essays on his fictitious method, in the first of which he announced that ontogenetic depth is A Biological Distance That's Currently Impossible to Measure. Yeah? So why was he presenting a poster at a serious scientific meeting in which he and his colleague claimed to have been measuring it? Sounds like scientific fraud to me.
But then, Intelligent Design creationism has been scientific fraud all along, so I guess he was just following hallowed tradition.