iPhone stuck in a microphone clip. Use a rag or folded piece of foam or tape to make it stick in the mic clip. Adjust the mic stand so the phone is around ear level/height. You can catch several versions of each practice. One with the iphone closer to guitar amp. One closer to drum set, etc. Or have each musician record their general areas all at the same time.
A CamCorder or any half decent video recorder should work also.