Year after year, shoppers are all atwitter about the big retail "holidays," also known as Black Friday and Cyber Monday. But there is another important day we should remember: Giving Tuesday.

Haven't heard of it? It's a global movement, dedicated to giving back, sharing the wealth and raising awareness. On December 3, retailers, organizations, and individuals will come together to support their favorite causes. Some may donate money, others will give their time, and still others will work to shed light on community issues through social media and other channels. Over 6,000 companies have joined up as partners, including the United Nations Foundation, an early adapter that has done a truly amazing job turning this concept into a well-known, well-organized, and completely awesome event.

And if you can't wait until December 3rd to get your giving on, don't worry: the altruism starts now and continues throughout the holiday season. More information on how to give back can be found online, both at their official site—givingtuesday.org—and on Twitter, Facebook, Pinterest, and even Instagram (use the hashtag #unselfie and #givingtuesday to promote your images!). Tell your friends, tell your colleagues, and let every shopaholic know: Tuesday is the new Friday.