The document announces a hackday event to take place on June 16-17th at Alexandra Palace in North London. At the event, participants will have 24 hours to build something and then present it in 90 seconds. There are no powerpoint presentations or prior review required. The goal is to spend a fun weekend collaborating and creating new projects. Photos from past hackday events show people actively working, presenting their projects, and enjoying surprise musical performances. The document encourages joining the upcoming hackday for a creative and social weekend event.