There are many things one can do at a comic book convention. Most of them have special guests, usually, but not limited to, comic book professionals. They can also have celebrity guests from television, movies, and more. Many of these guests will host panels about their comics or upcoming works, which is a great way to get information on your favorite comic books.
Buying comic books and related merchandise is also a big part of the convention, and one can find many deals on graphic novels, comic books from any age, statues, posters, and other gear. Collectors can also sell their comic books, but most vendors will be more interested in getting rid of comics, not buying more.
Another aspect of a comic book convention is the social aspect. You can come as your favorite costumed character and instead of being laughed at, you'll be photographed. After parties occur ever night at various locations, and ceremonies such as the Eisner's and Harvey's occur as well. A comic book convention, or "con" is a great place for a comic book collector.