Thanks, I think, to the approximately 20 million billion of you who wrote in to point out that we're celebrating Bentham's birthday on the wrong day. Seriously. Wikipedia now has it as February 15.
But... I was pretty sure that's where the Feb. 26 date came from, and sure enough, if you look back through the revision history in the Wikipedia Bentham entry, you'll find an older version with the February 26 date. Turns out that February 26th is the date in the old-style calendar; the same date in the new-style is February 15. There's a Wikipedia article that explains the difference.
We stand corrected, sorta.