Mine SHA256 ALT coins and pray they gain traction.
Well, that's the only option after these are unprofitable. The only other use for them would be to part it out or use it as a paper weight.
Re: sha256 alts being unstable: I think as asics get cheaper and old gen basics become unprofitable, they will switch over and protect sha256 coins. Kind of how Basic moved all the GPUs to scrypt. This is obviously purely speculation.
I don't particularly find any of the sha256 alts interesting, but who's to say they won't gain in value over time, it is anyone's guess. Or perhaps a new sha256 coin will come out that is actually a benefit to bit coin.