In terms of witnessing personally - actually being there:

1993, Alabama vs Ole Miss in Oxford. Ole Miss was 4-2 and had a very good defense led by Cassius Ware, and coached by Joe Lee Dunn. Alabama was coming off the end of their winning streak, just having tied Tennessee in a miracle "comeback" the week before to avoid the loss.

I was a grad student at Ole Miss at the time, and sat in the Ole Miss student section, decked out in Bama gear. By halftime, Ole Miss was playing their hearts out, and Alabama was stifled. Ole Miss led 7-6 and the reigning national champions had TWO yards rushing in the first half. Brian Burgdorf was quarterback for Bama, in front of Brian Steger (Mr. Fumblitis, the total package RB who had everything except hands).

Alabama managed a FG in the third and squeaked ahead 9-7...but they were in serious trouble, with the home crowd really believing Ole Miss was going to win.

And then....David Palmer. There's no other way to describe it. He just took the remarkably inept Alabama offense on his shoulders, and carried them all. He caught a long pass. He threw a long pass. He returned a long kick. The kid was electric, and Bama escaped Oxford with a 19-14 win.

If you aren't old enough to have seen David Palmer, he's probably an obscure name to you and you don't know why older Bama fans talk about him like he was a legend. He was a once in a lifetime player in college.