Gnu Tar: Extracting files into a single directory

[Dubious Dude]

Hello,

I want to extract a number of files from a tar.gz archive.
I want to extract them all into a single directory, regardless
of their path in the archive.  I haven't found a switch in the
gnu manual for this.  Is it possible?  I realize I can extract
them into the directories as per their full path, then move
them to a common directory.  But if gnu can extract them into
the common directory, I use that feature of course.

Thanks.