I know I've posted before about our hair-cutting technique: Jeremy does it at home, while Evan's asleep. Usually this works great. We lay him on a towel, roll him on his side, cut and clipper that half of his head, then flip him over and do the other. The next day Jeremy makes any necessary touch-ups.
This did not work for Evan's last hair cut--at the half-way point he woke up! So for a day, Evan looked pretty scraggly with one side basically finished but the other just had a few random clips. Thankfully, the next night he slept soundly through the remainder of the procedure.