Way too many to count. I don't recall very first game either, I know I was there in '72 for at least one game, the year Johnny the Jet won his Heisman.
Have ticket and photos from Colorado game in '73 (Nov 3, 1973)
Just some of the memorable home games I've attended:
NU vs Alabama 1977 Huskers hand Bear his only loss of the year.
NU vs OU 1978 Osborne finally beats the Sooners
NU vs Florida St. 1986 First night game in Memorial Stadium
NU vs OU 2001 Black 41 Flash Reverse Pass
NU vs CU 2008 Alex Henry 57 yarder
NU vs Missouri 2010 Roy Helu runs wild
NU vs Northwestern 2013 Hail Mary for the win.
NU vs Minnesota 2018 Frost first head coach win
Also attended Orange Bowl vs Fl State after '93 season
Orange Bowl vs Miami '94 National Championship game
Gator Bowl vs Clemson after 2008 season
Season ticket holder since 2011 so have been to most home games since then. Attended with my dad who had season ticket before then. When I got my own season ticket it turned out to be in the same section and row he'd sat in all those years. Just a few seats down. What are the odds of that?!? He's in late 80's now so no longer has his tickets. Great memories.