I think I'd have trouble thinking of the top 50 I've seen, let alone the top five, but I'll try.
1) 1998 Rose Bowl -- Easily Number one. As a game, it wasn't that exciting, but given the circumstances, and the fact that I was there with my dad, my brother, and one of my best friends, it was a transcendent moment. Every sports fan should have the opportunity to see their favorite team win a championship.
2) 1988 @ Ohio State -- The John Kolesar game. I was standing on the track between the stands and the back of the endzone, not more than 10-15 feet away from Kolesar when he caught the pass
3) 1997 vs Ohio State -- Woodson wins the Heisman. Two top teams, national title, big ten title, rose bowl all on the line and the best player I've ever seen played his best game. I still can't believe Stanly Jackson threw that ball.
4) 2004 vs MSU -- The Braylon Game. Pure magic under the lights.
5) 1999 vs Notre Dame -- There are probably a dozen games I could put in this slot or #4. This was a barnburner right up to the end, with ND trying to drive for a winning score when time ran out on them.