So I had a show Friday night, the standard multi-band, move gear on stage as fast possible, play the set, move gear off stage as fast as possible dance that I've been doing since I was 15 years old. I play in a progressive metal band that uses a fair amount of samples and has keys on a few sections that the drummer handles. For whatever reason, there was a MASSIVE ground hum from those channels during line check. Never had that issue before in our shows, even at the same venue. Worked with FOH to swap channels, try different cabling..... nothing. No samples or keys to monitors or mains without massive hum, so we split the difference and FOH took them as loud as possible without the hum overpowering everything else. So we fought through it, and then halfway through the 40 minute set, the keys/samples cut out completely, and there was just a steady, present hum. I'm not entirely sure what happened, and we'll check the drummers gear at our next rehearsal to see if something odd was going on that we can replicate and resolve, but that was not a fun gig.