I only go back to 1992 in the FF game, but can remember some good 3x miles on OnePass in fall 1993 and flying weekends to New York as mileage runs. Those 3x deals definitely helped.

But I'd say the late 2000/early 2001 Continental mileage bonanza was my own high-water mark. Calling in codes, wondering what'd post and what wouldn't, and getting 4x miles on some trips. I did one to Portland on a $188 RT that earned 31K total miles. There were stories of HKG RTs pulling six figures.

CO also had decent mileage sales back then, including 20K to DUS and 25K to HKG. One guy on the HKG flight turned around, in the front of coach, and asked, "Did anybody here pay for their ticket?" Felt like we were some traveling band of gypsies.

These things never last, though.