the fastest fly on tippet knot I've seen tied was by one of the guys at
TroutHunter on the HFork

get the fly on the leader,
hold the standing part in one hand on one side of the fly and the tag in the
other hand and side of fly ... the tippet taut
rotate the tag between thumb and first finger the six times ( takes practice
to get the count right, but not a lot of practice )
Bring the two hands together and --viola, the fly rotates six times and you
slip the tag through the now formed loop
can be done faster than saying "tie a knot" after the fly is on the tippet