ESPN provided some decent background information to allow me to analyze data on penalties in the Michigan-Michigan State game dating back to 2003. The results are very interesting, in my opinion, and also very telling about the differences in discipline and importance that is placed on this rivalry by the respective teams. See the below and draw your own conclusions:
(The "Against" row lists penalties called against Michigan and the total yardage lost and the "For" row lists penalties called against Michigan State and the total yardage gained due to these penalties.)
Based on the data, Michigan has averaged 4.14 penalties per game as compared to Michigan State's average of 8.71 penalties per game. That is a pretty large disparity and could have an impact on the game. Most glaringly, notice 2004 and 2006 data! Also, MSU appears to commit more penalties in Ann Arbor than playing at home in Spartan Stadium. This makes sense but its still an interesting tidbit nonetheless.
Another interesting discovery is that this game used to be played much later in the season than the past two years. I personally think its better played earlier in the Big Ten season like this year than later as it was in 2003.
Footnote: Does the disparity in penalties per game provide fuel for the fire that Desmond was purposely tripped in the end zone? (I'm still bitter about that one!)