Hacktoberfest is an annual celebration of the open source spirit, where participants are challenged to contribute four pull requests to participating open source projects during October in exchange for a t-shirt and/or a warm feeling. Sentry, an open source company, welcomes new contributors to its main repositories and issues, with resources available on its developer docs website. New contributors can participate by signing up, letting the team know they're participating, and utilizing the Discord channel for support. DigitalOcean hosts the event, which also features open roles at Sentry for those who enjoy hacking on the project.