The parks are super packed today and this weekend because there are multiple events going on at one time, whereas normally on this weekend it would just be Candlelight. Today there are RaverDay attendees around the parks, as well as likely pharmacists/Midyear Meeting attendees (their Midyear Meeting takes place in Anaheim starting tomorrow, and the attendees got great rates to stay onsite at the 3 DLR hotels), along with the usual Candlelight attendees. This was the first year in my recent memory that all of the Disney hotels were booked up this weekend. They have not been fully booked for the last several years on this same weekend. There were also probably extra people in the parks today, after the special limited edition pin event and signing in the GCH lobby (in the morning). The Candlelight crowds on their own can be daunting at times -- but not impossible to deal with. Throw in other events that will bring a lot of people as well, and you have a super packed weekend!