The description of something (or someone) as an 'E Ticket' means it was the best, or lived up to the hype.
Also referred to as an 'E ticket ride', this comes from the use at Disneyland Park from the late 1950s to the early 1980s of coupons lettered A to E, with the A tickets (a dime's worth, originally) paying for horse drawn carriage rides through the park, and the E tickets (worth four bits) gaining admission to a boat ride through pirates rhyming and looting and robbing and stealing.
The term was used throughout Southern California, and spilled, along with Valley speak, further into American lingo through its appearance in songs, films and TV. The Disney Resort conglomerate has capitalised on this by starting 'E-ride nights' at the park, in which groups of 5 thousand people had use of the park for a late evening. They also named a lounge at the nearby hotel the 'E-ticket Concierge Lounge', but the food and entertainment there must certainly not live up to expectations.
The most popular use of the description was by Sally Ride, commenting on her experience of the launch of the Space Shuttle Challenger in 1983 the best way possible: "Ever been to Disneyland? ...That was definitely an E ticket!"