Who called from 6128730000

Seemed to be intoxicated, and asked ridiculous questions before hanging up.

That is a phone number at Hennepin County Medical Center in Minneapolis Minnesota.

If you call outside of the hospital, this is the number that shows up on the recipient's caller ID

Called and left a message.  It was a rap that kept going until he got cut off.

Called me during class no message and tried calling back but no ringtone...

This is indeed an HCMC phone number.  It's a generic one that shows from patients making an outgoing call from the hospital.