When one attempts to drink a twelve pack of beer in under twelve hours at 12,000 feet or above. Under normal conditions, this is an easy task, but at altitude because of the lack of oxygen present, it becomes an immensely difficult thing.
After Sir Edmund Hillary climbed Everest, Hillary, to Sherpa:
"Finally, I can get one-beer crizzunk, Sherpa. Let's begin that twelve-hour challenge!"