Short answers, pulled from the story.
NASA used the Saturn IB launch vehicle for the Apollo program, testing the command and service module and the lunar module in Earth orbit before the larger Saturn V was ready. Later Saturn IBs carried three crews to the Skylab space station in 1973 and flew the Apollo portion of the Apollo-Soyuz Test Project in 1975.
The Saturn IB first launched on the 26th of February 1966, when SA-201 carried an uncrewed Block I command and service module on a suborbital test flight.
Engineers nicknamed the S-IB first stage Cluster's Last Stand because it clustered four Redstone fuel tanks and four Redstone liquid oxygen tanks around a central Jupiter rocket oxygen tank.
A cabin fire swept through the capsule during a launch dress rehearsal on the 27th of January 1967, killing the astronauts inside and damaging the command module. The mission, flown on vehicle SA-204, had been scheduled to launch on the 21st of February 1967.
The Saturn IB launched three crewed missions to the Skylab space station in 1973: Skylab 2 on the 25th of May, Skylab 3 on the 28th of July, and Skylab 4 on the 16th of November.
The last Saturn IB flight was the Apollo-Soyuz Test Project on the 15th of July 1975, when SA-210 carried an Apollo command and service module that rendezvoused in orbit with the Soviet spacecraft Soyuz 19.