Old Crusty

Old Crusty is the centerpiece of the playground, hence it has been shown in the lion's share of the series of 98th Street School (including the movies). It is a large combination jungle gym, slide, and swing set; it's almost impossible to envisage 98th Street School without it.

Old Crusty stood for a long time in the playground, until the Board of Education's new policies called for the playground to be torn down (this occurred in the episode "The Great Jungle Gym Standoff").

During this episode, despite the students, their parents, and the faculty's successful protest, Old Crusty came crashing down under the protesters' combined weight. The jungle gym was put back together and C.J. dubbed it "New Crusty".

Appearance
The "Old Crusty" that was shown to be an ancient, scruffy, and rusty dilapidated structure on the grass area of the playground of 98th Street School. This structure has been on the playground for, seemingly, an indefinite amount of time; "New Crusty" was constructed from the ruins of the one old.

The "New Crusty" is fresh, shiny, and is almost identical to Old Crusty. This was the one shown after its predecessor collapsed.

History
In the episode "Economics of Recess", the top of Old Crusty was occupied by C.J., seemingly making it her headquarters once she established a monopoly on the playground. This had both the Safety Rangers and Queen Barb's guards as watchers - this would imply that C.J. had formed a monopoly and all previous faction members worked solely for him. Brinklow and Rachel were both shown to be.

In the episode "Bachelor Rus", Rus commandeered it to be his home when he thought that he and his parents were going to move again. Old Crusty had some cloth draped in on the inside to simulate walls, as well as the basic creature comforts. When Rus moves out, Old Crusty goes back to normal.

Trivia

 * In the episode "The Great Jungle Gym Standoff," the structure old rusty was destroyed by the combined weight of the supporters. The new structure put in its place was - on the face of it - a restoration; C.J. herself christened it "New Crusty." Despite this, the kids go back to calling it "Old Crusty" later on in the series.
 * When New Crusty was constructed, it was done so from the ruins of Old Crusty. This is much like a metaphor for Phoenix from the Ashes.
 * The way that the structure is described could be perceived as personification.
 * In the episode "The Challenge", Principal Prickly's brother's school, which is like a mirror universe to his own, there is an identical jungle gym named Old Rusty.