Lotus 1-2-3 Day is celebrated annually on January 26 to commemorate the release of the influential spreadsheet program, Lotus 1-2-3. This software revolutionized personal computing by combining spreadsheet, charting, and basic database functionalities, making it a must-have tool for office work. The program significantly impacted how individuals calculated and organized data, paving the way for future spreadsheet applications, including Microsoft Excel. Celebrations typically involve recognizing the ease and efficiency that Lotus 1-2-3 brought to users' work lives. The day serves as a reminder of the program's historical significance in the evolution of office software and its role in the success of IBM's personal computers.