In reply to Flash from the past:
In my experience there are varifocals, and varifocals. I have the 'Elite' varifocal lenses from Specsavers and it took me less than one evening to get used to them at the climbing wall. My g/f bought the 'standard' lenses in her varifocals and simply can't wear them, even just around the house. The differences in the sizes of each focal length section, and the 'blend' between them, is vastly easier to get used to with the more expensive lenses.
I also use my varifocals for cycling, and under goggles for skiing. For sports I have a semi-wraparound titanium frame which is nice and light, with the legs adjusted to what the assistant called a "skullcrusher" shape - not nearly as painful as it sounds, but it keeps them secure on my face. I also use a neoprene glasses retainer for climbing, to avoid the risk of them dropping off when I'm searching up, down and around for holds.
I did experiment with multifocus contacts but, although I had no trouble getting them in, I couldn't for the life of me get the damn things out. A pity, because the sight correction seemed to work very well when I did have them in.