The Electronic Entertainment Expo or E3 is held every year in May in Los Angeles, CA. E3 is one of the largest video game conferences in the US, if not the world.
As Piro and Largo experience it right in the first strip of Megatokyo, E3 is not open to the public. Only qualified industry professionals are allowed to attend. This policy of exclusion may be said to be the catalyst for all the events that follow, as shown in strip 8. It provides the reason for Largo to get drunk (not that Largo really needs a reason), and thus Piro with the opportunity to get out of the country.