The Apollo 16 UFO footage was 'some' of the best evidence as proof of their existence at the time, however, recent analysis showed that what was actually caught on film was nothing more than the floodlight/boom attached to the command/service module.
A lead from a Google Alert for UFO led to a visit to a nice blog called Science & Technology which is a collection of videos, some of which are of interest to Forteans.
It would certainly appear that this famous video, which I'll admit had me going for a long, long time, is totally mundane... as it says above from the makers of the clip... it's just the lighting boom playing nasty little games with our hungry and sometimes a teensy bit too credulous minds. Actually, now that the rose glasses are off, it does appear a mite less exotic than it did... although it still looks cool. The analysis seems pretty damn conclusive. Hey, looks like they solved one! Bravo, guys... now let's see you figure out what that fastwalker was... hehehe... good luck!