1. The Panels
Panels offer audience members a chance to be in a room with their favorite actors, directors, writers and producers of television shows, movies, games and comics they are obsessed with for an extended period of time. The panel discussions are often incredibly entertaining as well as informative.
2. Amazing Cosplay
Cosplay gives people a chance dress up as various fictional characters even though it's not Halloween. Some cosplayers spend months creating costumes that are practically perfect copies of those worn by different characters, while others create a unique twist that helps them stand out from the crowd.
Some are funny.
Some are serious.
Some are simply beautiful.
No matter the costume, it is certain that every one is crafted with care. Even if you don't cosplay yourself, it's fun to simply look at other people's costumes and most people are happy to take a picture if you want to pose with someone you find particularly awesome (just make sure to ask politely first).
3. Free Swag
Everyone loves swag, especially when it's free. What makes the swag at Comic-Con special is that it's swag that fans actually care about and oftentimes limited edition. Although the wait for popular panels can last hours, the swag definitely helps make it worth it.
4. The Not-Free, But Still Totally Awesome Swag
Of course, there will also be tons of booths with merchandise for sale. Like the costumes, some people work for months creating sweet goods to sell. Although it is possible to find a lot of the things offered on the web, some items are exclusive and I'm a big fan of not having to pay for shipping.
In conclusion, if you're not going to Comic-Con 2013, you're missing out on an amazing experience and probably want to throw yourself into a volcano right now.