Observe. Hack. Make. or OHM in short was an outdoor hacker conference that took place in the Netherlands from July 31 to August 4, 2013. This conference was the most recent event in a sequence that began with the Galactic Hacker Party in 1989, followed by Hacking at the End of the Universe in 1993, Hacking In Progress in 1997, Hackers At Large in 2001 What the Hack in 2005, and Hacking at Random in 2009. With 3000 tickets sold the camp was completely sold out weeks before the camp started. With 700 more tickets compared to the last camp is this the biggest Dutch hacker camp yet.