OpenAI CEO Sam Altman was pleasantly surprised as Stanford students serenaded him with "Happy Birthday" during an event. In a video, Altman, who turned 39 on April 22, smiled awkwardly, jokingly calling it "less interesting." The clip garnered over 6,000 views, showcasing his relatable reaction. Altman, a Stanford dropout turned billionaire, gained fame for OpenAI's ChatGPT.