National Solitaire Day is celebrated on May 22, primarily in the United States, to honor the popular card game solitaire. This day recognizes the game's historical significance, particularly its role in teaching users how to operate a computer mouse when it was introduced on Microsoft Windows. The day features various activities, including playing solitaire online, hosting matches with friends, and organizing solitaire-themed parties. Microsoft has commemorated the event by offering special bonuses in the game and sharing video testimonials from fans. Solitaire, also known as 'Patience,' has a global following with over 242 million players, and it continues to be a beloved pastime.