Since you said in another comment your area of interest is medicine, you could study statistics (and work on statistics problem sets during boring lectures—problem sets are just a type of puzzle that also build more useful skills besides keeping your brain busy).
Since you said in another comment your area of interest is medicine, you could study statistics (and work on statistics problem sets during boring lectures—problem sets are just a type of puzzle that also build more useful skills besides keeping your brain busy).
That’s an excellent suggestion! My statistics skills definitely need some polishing.