According to the modern version of the traditional calendar, today is the first day of spring. Known as Setsubun, it is marked every year on February 3.
We don't bother too much with the bean throwing ritual as it's mostly for the kids (and parched soybeans aren't our favourite snack), though I did don my ogre mask. But I totally approve of the custom of ehomaki, the special norimaki sushi rolls that should be consumed on this day of days for good luck.
The convenience stores had stacks of them for sale this morning for as little ¥390 apiece...
But the way I look at it, if a year's worth of good luck is at stake it's worth paying a bit more and actually enjoying what you're eating. So I splashed out on a deluxe ehomaki...
It was stuffed with fine strips of eel and chunks of tamago-yaki omelette. A bit sweet (what do you expect?) but made with good quality vinegar, and with undyed gari ginger on the side.
You're supposed to eat it all in one sitting, without cutting it (that would sever your luck) and also face in the correct auspicious direction while you're eating it — I believe it's east-southeast this year. I figured that facing my laptop would be lucky enough.
I did have my mask though...
Update (2013): I just came across this good article giving the background and history of Setsubun.