Oh, yeah, didn’t you know? Blogger Appreciation Day takes place every February 29th (so, obviously, it’s a leap year kind of thing); and you celebrate it by… well, of course, by letting your favorite blogger know how much you appreciate him or her. A little bit of cash in his or her tip jar is also traditional*, and supposedly also good luck for the giver.
Good thing that I mentioned this ahead of time, huh? – It’ll give people time to prepare.
*I think that it was Terry Pratchett who noted that traditions have to start sometime.