Rose Campion, Bloody Mary, Bloody William. Lychnis coronaria
When you cut back the stalks on the campions after blooming, you can cut sections and root them. You want a pair of leaves on a piece of stalk that is about 2-4" long. Just stick them in the dirt in a kinda shady place and move them when they are bigger, in the fall. These cuttings are about 1 month old and you can see the old tattered big leaves and the new growth in the center. These will bloom next spring. And before somebody jumps me on this, I will say that I know this to work in the Atlanta area. Your zone may differ!
This also works really well on penstemons and alpine wallflowers.
I just posted a pix of the 'babies' over on the alt.binaries.pictures.gardens newsgroup