Since its opening in 1955, eight people have died in Disneyland, seven of which were results of their own negligence, the other was killed by a faulty ride. Here's the list and a description, courtesy of snopes.com - The Urban Legends Reference Pages.
- May, 1964 - Mark Maples, 15, was killed after standing up on one of the bobsleds on Matterhorn Mountain. He unbuckled his seat belt, and lost his balance when he stood up, cracking his skull and three ribs. He died three days later from internal bleeding.
- June, 1966 - Tomas Cleveland, 19, died while trying to sneak into the park. He climbed the parks outer fence, and got onto the monorail track. Had there not been a monorail on the track, his plan would have been fool-proof.
- August, 1967 - Ricky Yama, 17, was crushed to death by the People Mover while he jumped off the train in a tunnel. He slipped and went crunch.
- June, 1973 - Bogden Delaurot, 18, died while swimming across the Rivers of America after getting drunk on Tom Sawyer Island. His body was found the next day.
- June, 1980 - Gerardo Gonzalez died pretty much the same way as Rick Yama died. Gerardo jumped off the People Mover, slipped, was crushed to death. Nobody witnessed this, so his body was dragged behind the People Mover for hundreds of feet until an operator noticed.
- June, 1983 - Drunk off his ass, Philip Straughan, 18, stole a motorboat that was parked in a cast-only area. He drove it around a little, smashed into a rock. He was thrown into the water, where he was too inebriated to remember how not to drown.
- January, 1984 - Dolly Young, 48, was thrown out of her bobsled on Matterhorn Mountain and got her head and chest pinned under the bobsled behind her. Investigators say that her seat belt was unbuckled, but since nobody was in the bobsled with her, they could not tell if she jumped deliberately or not.
- December, 1998 - I won't make fun of this one because this was not caused by the person's own idiocy. Luan Phi Dawson, 33, was struck by a cleat used to keep the sailing ship Columbia at dock when it was ripped off of the dock by the ship. (a la Men of Honor with Cuba Gooding Jr.) Dawson was declared brain-dead two days later, and died when taken off life support.
Well, there you have it, a complete list of everybody who has ever died at Disneyland (up to 2001). Wow, that's kinda morbid.