cmu (carnegie mellon, not central michigan) has the same tunnels as well - i've been down there both legally (working for datacomm) & not so legally (drunk & wandering). cool stuff down there, you can make it across most of the campus... the best entrance is in the back of the college of fine arts behind the bulliten board, the whole thing opens up.
dont ask me about drinking tequila on the roof of wean hall tho...
-hoss