Last Saturday at Chogye Sah Temple here in Manhattan, I showed up for their monthly 1,000 bows practice.
I'll let the Kwan Um School website explain it better than I can:
From the Dharma Mirror - Manual of Practice Forms:
Prostrations could be likened to the 'emergency measure' for clearing the mind. They are a very powerful technique for seeing the karma of a situation because both the mind and the body are involved. Something that might take days of sitting to digest may be digested in a much shorter time with prostrations.
I showed up at 5:00 pm and Myoji Sunim (the Abbess of the temple) was there encouraging everyone as they started bowing. Her chanting and hitting of the moktak provided an intensely effective focal point to the practice. For the second hour (yes it takes about 2-2.5 hours to do 1,000 full prostrations) the chanting was done by Myong Haeng, the Vice-Abbott.
There's sitting and walking meditation, chanting, and bowing.
This isn't for the physically weak--as of today (4 days later), the soreness in my legs is just starting to subside. I don't recommend such practice for anyone with leg, knee, or foot problems.
While I was skeptical at first I can easily say now that this practice was the most demanding and mind-clearing of my life.