During the Apollo-Soyuz test program, the Russians and Americans worked together on missions - and one big objective was to dock Apollo and Soyuz craft together.
Afterward, however, there seem to be very few, if any, instances of two spacecraft docking directly (not through a space station). Are there any occurrences of this after Apollo-Soyuz?
Gemini tested docking with an Agena Target Vehicle, and Soyuz earlier had demonstrated docking as each program needed to prove docking for future operations.
The docking practice/technology was needed for the eventual moon mission, as the Lunar Module and Command module would dock, soon after TLI, to remove it from atop the third stage. Then of course once in lunar orbit, and after the lunar surface mission, the LEM would dock back with the Command Module to transfer crew.
China being the next on the scene decided to use a docking target as well, just a bigger one, that could also act as a basic space station, Tiadong-1.
So the simple answer is no. Turns out, it was not really needed.
The ATSP docking was entirely a political stunt, which in hindsight did prove to be of technical value, as the module Apollo brought with it to dock provided information for the basis of the docking module added to the Spekctr module on Mir for use by the space shuttle.
The next possible opportunity might be the proposed asteroid missions using two docked Orion that has been vaguely suggested.
Should also mention that mission plans were drawn up to do this on an emergency basis during the Shuttle program. The post-Columbia plans included a docking at the ISS, and there is mention in the Wikipedia article (without much in the way of references though) to plans before the Columbia accident for direct rendez-vous between the two shuttles.
