National Grammar Day is Wednesday (March 4).
A day set aside for promoting correct (or, at least, standard) English grammar and usage is the brainchild and pet cause of Martha Brockenbrough, who founded the Society for the Promotion of Good Grammar (SPOGG) and writes the SPOGG blog.
National Grammar Day could unleash our pedantic impulses. Indeed, some people might take metaphorical red pens in hand to delete errant apostrophes and chastise those who would say, "Please tell Mary or myself ..." But we don't have to become Miss Thistlebottom, Theodore M. Bernstein's mythical promoter of outmoded and bogus rules of English usage. I would like writers to use lay and lie correctly and to get out a dictionary to be sure of the homonyms they use, but I refuse to get my unmentionables in a bunch over some deviations from the standard, especially in everyday speech.
Baltimore Sun editor and blog writer John McIntyre has some advice and guidance for National Grammar Day. McIntyre reminds us that "English has rules, but not as many as you think."
In this link, you will find a vigorous dissenting opinion about National Grammar Day at Language Log. I agree that the study of English and its structure and variations is much more interesting than the memorization and enforcement of schoolroom grammar.
Still, I like Martha Brockenbrough's idea, and I will celebrate National Grammar Day this year.
Speaking of Martha, her book, "Things That Make Us [Sic]," was published late last year. It's a breezy and humorous work that grew from her own efforts to promote clean, correct, well-punctuated writing. Among other things, she explains regular and irregular verbs with a short history of strong and weak verbs and gives examples of some of the most common problems. Near the end of the book she gives "The Ten False Commandments of the English Language," including "Thou shalt not end a sentence with a preposition."
I found her section on common Latin phrases helpful.