You can have some of mine! Thanks to my father, I have inherited HUGE calves... but fortunately, my sister inherited even larger ones

It's a real struggle to find boots that will zip up easily.
But seriously... I think the calf muscle is really hard to build, probably one of the hardest places on your body to increase in size.
I reckon cycling would help -- cyclists have great legs! And doing calf raises where you stand on your toes and hold for thirty seconds is a good starting point. Can hold weights in your hands as this gets easier.
You probably need weight machines at the gym targeting that specific muscle area to see a real improvement, though.
Just keep moving! And don't be lazy...
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SW: 74.3kg - 1/1/09
CW: 71.1kg - 3/5/09
GW 62kg