Global Graph Celebration Day (GGCD) is an annual event held on April 15th to honor Leonhard Euler, the Swiss mathematician who invented graph theory. The Neo4j community and graph enthusiasts worldwide organize events to celebrate Euler's birthday, which has become a global movement with over 60 events in six continents. The event encourages participation through organizing local events, presenting or helping organize alongside meetups, attending events, and participating in various activities such as hackathons, games, and whiteboard brainstorming sessions. The Neo4j Developer Relations Team provides resources and support to help organizers plan their events, which are listed on the GlobalGraphCelebrationDay.com website and included in a community graph.