In college.. hundreds. I had a really tough karate teacher. After any particularly bad day for our group - in addition to the 10 knuckle pushups we'd do at a time, every time *anyone* made a minor mistake (not a tight fist, stomach muscles not tight, stance isn't perfect, etc.) - our punishment would be 100 consecutive knuckle pushups, followed by 100 sit-ups (2 sets of 50) on an inclined portion of the indoor track.
A kid on the 3rd floor of my dorm back then challenged the rest of his floor on a bet - he could do more consecutive pushups than the rest of his floor (30-some people) combined. He won & had a light girl sitting on his back while he matched the last couple of guys on the floor.
Today? I'd be lucky to do 20.