What a surprise:

pgportable1.PNG

Headed over to the sourceforge page, downloaded, installed (which is just a matter of next/next/next)
: pgportable2.PNG

Not really the latest patchset but far more than I expected 🙂 So I can do tests on a Windows machine where I do not have any permissions to install software. Great. If you prefer a graphical client then go ahead and use the portable version of PgAdmin.