Stripped Campy Chorus Cup...

You mean the tiny little teeth in the thin aluminum BB shell? (I had it
happen on an Athena. The irony of such a dumb design named for the
goddess of wisdom nearly choked me!)

Not a hack saw but a Dremel tool and a lot of emory cutting disks.
Carefully cut a series of wedges until you can start breaking out
pieces. Eventually, you get enough metal out so that the assembly can
be driven out by pounding with a hammer from the other side. It takes
about an hour. Once the assembly is out, you might be able to get the
remainder of the cups out by turning with a mallet and cold chisel. (In
my case, once the assembly was out, I could turn the remnants by hand.)

You'll need to get the BB threads re-faced when you're done.

steveb said:

I've been told that these can be hacksawed out.
How is that?
Cutting through the axle as well?