Time Tunnel/Triumph of Man
In 1964 and 1965, the World's Fair visited New York City. One of the exhibits at the fair was the Triumph of Man, the exhibit that would become the Time Tunnel at COSI.
Here are pictures and an article when The Triumph of Man opened at COSI.
Some of the characters from the Time Tunnel made it to The Ohio Railway Museum.

The Presidents
A decade after COSI closed, Corey Aumiller and Dan Gerdeman got hold of several of the old COSI presidents and created an amazing display called, Time Tunnel. They are still on display at Shoppes on Capital Square, 65 E State St. between the Sheraton and Ohio Theatre.
Shortly after COSI closed, they sold off many of the presidents. Here are how they looked at that point.

Durell Street of Yesteryear
This article explains what the Street of Yesteryear will be and shows a model.

Coal Mine
The Coal Mine was made possible largely with help from The Jeffrey Manufacturing Company.
Here are pictures and an article when the Coal Mine opened at COSI.

Elephants
After COSI moved, many of the elephants made their way to the Columbus Zoo.

Cracker Jack
After COSI moved, they lent part of the Cracker Jack Collection to the Wyandot Popcorn Museum in Marion, Ohio.

History of COSI Exhibits
The new COSI opened up with an exhibit called The History of COSI which contained a ton of stuff from the old COSI. This closed in 2004.
Some of COSI's exhibits, including a small recreation of the coal mine returned for the 50th Anniversary History of COSI exhibit.

Central High School
Here's Central High School before COSI moved in.