A colleague of mine agreed to using Subversion (SVN) for our little project, but only if he doesn\'t have to install it. He has a U3 USB stick where he keeps the project fil
I'd go with the copy and paste the bin folder from SlikSVN.
EDIT:
Seems like SlikSVN is the underlying platform behind several graphical SVN clients. In my experience it seems stable and reliable.
Specifically, the bottom link on this page seems to be a non-install/xcopy precompiled package (although I haven't tried this one myself, only inspected it). It does not appear to be the newest, though. You might do your friend a favour by installing the newest SlikSVN on your own computer, and then share the bin files with your co-dev.