Now that it's March 2nd, it's time to march forth with today's snippets:

* There's a great commercial flashcard program for Mac OS X, called Mental Case. It ordinarily costs $29, but if you go to this page in cool OS X apps before 7:30 AM PST/10:30 AM EST on March 3rd, you can save 45% on it! Just scroll down and click on the Buy For ONLY $15.95 button to get the discount! This is a great deal, especially considering that their educational discounts only get you $10 off.

* If you enjoy the classic 15 puzzle, check out Puzzlet Factory! They have over 10,000 picture sliding puzzles for you to solve. You can create your own, as well. If you enjoy this site, but want your puzzles on the go, try Puzzlet Factory's new iPhone gallery.

* If you've mastered the Knight's Tour, I've got another variation for you. This one is called Knight Switch (Flash required). On a 3 by 3 chessboard, all you have to do is switch the position of the gold knights with the blue knights. Both the timer and the small chessboard make this trickier than it sounds.

* You've probably heard about the song chart meme. The idea is to take a popular song, and convert it into some form of chart, such as a graph or a flow chart, that displays the song. There have been many of these here and there, but now there's a great Song Chart Flickr Pool. Among my favorites are the American Pie Chart, the chart of countries that should and shouldn't cry for me, things I would do for love, and the Luftballoon chart.

* Earlier this year, Neatorama posted a great look at The Wonderful World of Early Computing. It's an amazing look at the devices we've created to deal with our numeric needs. This is a sort of physical equivalent of BetterExplained's A Quirky Introduction To Number Systems. If you're interested in a great history of the early digital computer scene ('70s and '80s), check out Atari Archives, especially The Best of Creative Computing, volumes one, two and three. One of my favorite article here is The World In Your Own Notebook, in which a 1970's computer user theorizes about the future possibilities of a personal notebook-sized computer. It makes me want to grab a MacBook Air and hop into a time machine.

That's all for now. Don't forget, in less than two weeks, it will be Pi Day, Einstein's birthday and Grey Matters' 3rd blogiversary!