I used to work with at least a couple dozen MBA's from 1 school, they gave me this advice for bus school:

1) don't lose your coding skills (I was good at perl/awk, APL, C and Fortran). This I did

2) concentrate on linear algebra, stats/prob, calculus (this i didn't)

3) take law school classes (this i did, they were gnarly)

tl;dr your 2nd year you can do pretty much whatever you want. You can make it a profoundly intellectual experience, or start your business, or whatever