Standing calf raises are an excellent exercise for rock hard calf muscles - just like your friend's.
Here's a good visual of a barbell standing calf raise. This is exactly what your friend does, only this one is being done in a power rack with a barbell. If you can't afford a gym membership or want to workout at home, you can easily use a step or a platform to do your calf raises on. To get the full affect, it's just important to raise your heels by extending through your ankles as high as possible, and then lower your heels back down until you feel a good stretch in your calves. It will burn at first, but try to do a set of 10 repeititions to begin.
Anna
Editor@FitnessGear101.com