A Reddit user named Rachel got the surprise of a lifetime when she discovered the identity of her Secret Santa: Microsoft founder Bill Gates.
(Read more: Six wearable tech gift ideas )
The billionaire was assigned to her in the website's annual Secret Santa Gift Exchange, and Rachel had known him only as "Bill."
Gates made a donation in her name to the nonprofit Heifer International. He sent a box with a stuffed animal representing the gift, accompanied by a photo of himself in front of a beautifully decorated Christmas tree holding the toy and a note to Rachel. A National Geographic travel book was also in the box.
—By CNBC's Cadie Thompson. Follow her on Twitter