If you want to enable macros be my guest, I am not sure how to do it.
I'll think it over, a sheet to group bands by music genre, and some rule sets to avoid scheduling all the same genre at the same time, and band members that are in multiple bands, and other considerations and a big green GO button might be quite doable. Then again, excel macros are all in VB, so yuck =P
If you are going to do it... The first thing I do when planning my attack is to see which acts are only playing once and add them in to the schedule.