OK, this first part is going to fall into the TMI category, but oh well... I have hairy arms. That said, I have put my wookiee-like guns (OK, more like pea shooters) to good use; they're great for testing blade sharpness. It's a variation of the HHT: the TTH or "Trimming the Hedges" test.

Holding the blade about half an inch above my arm (so the cutting edge is half an inch above the skin), I move the blade parallel to my arm. If the blade successfully "trims the hedges", it's pretty darn sharp. You can also tell by the amount of tug before the hair cuts how sharp the blade is. Too much tugging means a ragged edge, and the hair got caught in a "tooth". When you can see and hear the hairs being cut with no tug...yeah, that's sharp.