I'm just going to go with a few memorable ones...
2004: Purdue 41, Notre Dame 16. This was Orton's senior year, and Purdue just hounded the hell out of Brady Quinn all day long. Quinn was a good QB when he had protection, but tended to fold under pressure, and Purdue brought the heat. The memorable point was Purdue backed up on their own 3, Orton throws a fade to Taylor Stubblefield on the right sideline (whose defender falls down during the catch) and rolls 97 yards for the TD. It was just one of those days for ND.
2008: Purdue 62, Indiana 10. Joe Tiller's final game, and Curtis Painter's final game. The team wanted to send them out in style, and did so with an utter dismantling of Indiana. This wasn't a "ranked vs ranked" game. In fact, it was two 3-win teams facing off (Purdue improving to 4-8, Indiana finishing 3-9). But it's a rivalry, and even when both teams aren't that good, you still want to destroy your opponent.
2003: Michigan 30, Purdue 3. This was an unexpected beat-down. In 2003 Purdue was quite good, with a solid running game, elite defense, and ranked #10 in the country at 6-1 coming into the game. Purdue was expected to be competitive. I was at a fraternity brother's wedding, and was hanging out in the basement of a church listening to the game on the radio with the groomsmen. We all had such high hopes, and were almost stunned by the way Michigan just bullied us on both sides of the ball all day long. Much like my fraternity brother's marriage, this one wasn't right from the start.