All three of mine have sentimental value, since I attended all three with my dad. Dad never shows much emotion watching GT sports at home, but something about being there just brings the enthusiasm out.
1. Somebody help me with the year (95 or 96), but we watched C.J. Williams score maybe three 4th quarter TDs to beat NC State in the rain. Might not have been the best game or best atmosphere (small crowd, crappy weather) but nevertheless it was the first time we attended a game together by ourselves, and I had a blast. I was 14 or 15.
2. 2006 Maryland (the Michael Johnson game). Just me and dad again. Thought for sure we were toast after MD answered our go-ahead FG with a loooonnngg pass play down the east sideline. A safety (name?) made a tremendous play to chase him down, and we all know how MJ single-handedly finished it. (Loudest I'd heard BDS at that time.)
3) 2011 Clemson. Hard to choose b/w this one and 2006 ND. I'll go with this one due to the win, and coming in with zero expectation of beating them.