If you walk by an Apple Store and notice that it looks more colorful than usual, know that the bright red logo represents a worthy cause. Starting today, more than 400 Apple stores across five continents are going red in support of World AIDS Day (Thursday, December 1) and the 10th anniversary of (RED).In 2006, Bono and Bobby Shriver cofounded (RED) to fight the spread of AIDS. A large portion of the fight involves raising money to provide antiretroviral medicine, which costs 30 cents per day, to mothers and children in sub-Saharan Africa. Apple, which is one of (RED)'s sponsors, is making it easier to contribute to this important cause (while nabbing the gifts you'd be buying anyway), through December 6.Whether you're planning to buy an iPhone 7 or a new pair of Beats, make sure you use Apple Pay when you check out. Apple will donate $1 to (RED) for every purchase. There's also some brand-new (RED)-themed merch , so you can deck out your gadgets in a seasonally appropriate color and support the cause. Among the new products are a red leather iPhone SE case, a red iPhone 7 smart battery case, and cherry-red Beats headphones and speakers.The app store will also look way more red than usual, thanks to special (RED) content on popular games including Candy Crush Jelly Saga and Angry Birds 2. Spend money to power up in the games, and 100% of those proceeds will also go towards (RED) — a win-win.If you want to show your support with your purchases but you don't need any Apple gear, check out some of the holiday options from other (RED) partners, such as Mophie and Deborah Lippmann. It's just one way to get in on the season of giving while crossing holiday shopping off your to-do list.