Post-college (and most in my life so far): Several years ago, I had to upgrade an enterprise software application for a hospital. The upgrade started at about 10:30 pm, and I made the mistake of not getting any sleep beforehand, so I had been up since about 6:30 am. The upgrade did not go well, and it was 5:30 pm the next day before my bosses would let me go home. So, about 37 hours.
During/before college: About 30 hours one time in the summer between my "junior" and "senior" years in college. I enrolled during the summers to finish faster. I pulled an all-nighter to finish my Advanced English term paper, handed it in and took the final, on which I managed an A, giving me either an A or B overall in that class if I remember correctly.
The best sleep deprivation anecdote I can give didn't happen to me, but to my friend, who was staying in a dorm room down the hall from my own. It was finals week (a different semester), and he had been taking No-Doz to stay awake, take his finals, and work on our music hobby. I stayed up late that particular night and was finishing up some artwork on one of our goofy "dorm studio" cassette "releases." At about 1:30 am, he walked in, another No-Doz in hand. At this point, he had been up for 72 hours. He took it, paused for about 30 seconds, and said, "Y'know, I don't think this one's gonna work. I'm gonna lay down for a second. If you finish, just pull the door to..." He passed out with his head still six inches from the pillow, and slept for about 36 hours straight.
No-Doz is no joke, people.