The Mig-25 was fairly famous for using vacuum tubes - initially this was seen as rather funny in the West then people realised that they actually had some distinct advantages, including alleged resiliance to the EMP from nuclear explosions:
There are reports of ground crews for MiG-25's drinking the hydraulic fluid for the planes, which was apparently based on ethanol. Truly an aircraft for those with a discerning palette.
or a lifesaver for aircrews stationed in "dry" countries like Yemen :)