Gemini 8 recovery soon after splashdown on March 17, 1966. Featuring future moonwalkers Dave Scott, and some guy named Neil Armstrong.
Below is a picture from their capsule before they attempted to perform the first ever docking with the Agena target vehicle. I have a framed print of this picture autographed by Dave Scott.
Soon after they docked with the Agena, there was a problem.
After the Agena began execution of its stored command program, which instructed the Agena to turn the combined spacecraft 90° to the right, Scott noticed that they were in a roll. Armstrong used the Gemini's OAMS thrusters to stop the roll, but after the roll stopped, it immediately started again. Gemini 8 was out of range of ground communications at this time.
Armstrong reported that the OAMS fuel had dropped to 30%, indicating that the problem could be on their own spacecraft. With concern that the high spin rate might damage one or both spacecraft or even cause the propellant-heavy Agena to rupture or explode, the crew decided to undock from the Agena so they could analyze the situation. Scott switched the Agena control back to ground command, while Armstrong struggled to stabilize the combined vehicle enough to permit undocking. Scott then hit the undock button, and Armstrong fired a long burst of translation thrusters to back away from the Agena.
Without the added mass of the Agena, the Gemini's rate of spin increased quickly. Soon after this, the spacecraft came in range of the ground communications ship Coastal Sentry Quebec. By now the spin rate had reached one revolution per second, blurring the astronauts' vision and putting them in danger of losing consciousness or suffering vertigo. Armstrong decided to shut down the OAMS and use the Re-entry Control System (RCS) thrusters to stop the spin. After steadying the spacecraft, the crew tested each OAMS thruster in turn and found that Number 8 had stuck on.
Almost 75% of the reentry maneuvering fuel had been used to stop the spin, and mission rules dictated that the flight be aborted once the Reentry Control System was fired for any reason. Gemini 8 immediately prepared for an emergency landing.
Three hours after splashdown, the recovery ship had the spacecraft on board. The astronauts were exhausted, but had otherwise survived the flight in good condition.