Hacktoberfest, now in its fifth year, is a month-long event celebrating open source software, with DigitalOcean returning as a partner and Twilio joining for the first time. Participants can earn a limited-edition shirt by submitting five pull requests to open source projects between October 1-31, with the first 50,000 successful participants receiving the prize. Last year saw over 30,000 participants from 119 countries, contributing nearly 240,000 pull requests ranging from documentation improvements to new features. Those new to open source can refer to a dedicated guide, and participants are encouraged to share their experiences on social media using #hacktoberfest. More details, including terms and conditions, are available on the Hacktoberfest website.