Recently I was looking for a small and portable FTP server that needs no installation and can be configured within a minute to perform some file transfers. To my own surprise there weren´t many options on the market and so I ended up using Smallftpd 1.0.3. It seems to be really old though the Sourceforge page speaks of an update in 2013.
Anyway – it did exactly what I wanted, needed no installation, supported passive mode and even a link to a dynamic DNS service.
Smallftpd @ Sourceforge – http://sourceforge.net/projects/smallftpd/