This site contains a stunning series of photos of an abandoned Japanese amusement park. The first few pictures of a rotted roller coaster are especially creepy as they were taken in the morning fog. page 1 - page 2 - page 3
Defunctparks.com features many snapshots of parks in their heyday alongside the current state of rot: Rocky Glenn Park in Lackawanna County, PA - Mountain Park in Holyoke, MA - Idora Park in Youngstown, OH - Chippewa Lake Park in Chippewa Lake, OH .
Pacific Ocean Park decimated through time.
Here is a promotional film for Santa's Village (mov. file) from Extinct Attractions, a site that preserves Disneyland's and Disney World's past through interactive DVD documentaries. They also archive information, pictures and sounds of theme park rides, attractions and brochures. Browse around a bit, they have a few more video clips.
Take a listen to Goosy Goosy Gander (mp3) and The Happy Dragon's Tongue (mp3) - they are part of a collection of field recordings from theme park rides and attractions recorded and compiled by Melinda Simon and Mark Fay and released as "Songs for Little Ones" on Dish Recordings in 1997.