1) 2009 BCS NC Game at the Rose Bowl - Being California born/raised, and also raised in a USCw family, I learned the history of the Crimson Tide in the Rose Bowl once I started attending UA. Always wanted to see them play and win in the stadium, and got that opportunity in 2009. It wasn't the best game from an entertainment value that I've seen in person (that goes to USC-Texas in 2005), but I'll never forget it.
2) Rocky Block - Super tight game. I was in the student section with my girlfriend (now wife), and she refused to watch the final FG attempt, covering her eyes and turning around. Once Cody blocked it, I've never seen so many people randomly hug and high-five others in a football game.
3) 2016 Alabama vs. USC - Special to me b/c my family are all USC graduates, and I graduated from Alabama. My dad always talked about watching Alabama destroy USC in LA when Bear surprised everyone with the wishbone offense. Sadly for him, he witnessed another blowout with me. Sitting in the USC section ("These are your people?" as my wife commented) made it sweeter.
4) 2011 Iron Bowl - My BIL was a student at AU (only b/c of his agronomy/soils degree, not b/c of fandom) and got my wife and I tickets to the student section for the Iron Bowl. Super enjoyed that game with all of the other students not saying anything!