A convention is an event that usually takes place during two or three days and is dedicated to one or more TV show(s) / movie(s).
Organized mainly by fans associations, conventions give fans the opportunity to participate in Q&A with the actors, take pictures with them, get autographs or spend a moment with them during a Meet & Greet.
A TV show/movie convention, is also the opportunity to participate to many activities during the event : quizz, lottery, karaoke... while meeting new people.
They also allow fans to chat with one another about a same center of interest and to return home with a lot of unforgettable memories.
To participate to a convention, it's mandatory to get a pass on the ticketing of the organization in charge of the event.
It is important to remember that without a pass, you will not have access to the convention. If you purchased extras without this precious pass, you are not going to be able to use them and you will lose money unnecessarily.