2X Client portable, now "Parallels Desktop is a remote desktop client that can be used to connect to your remote desktop servers. The portable 2X-Client "Parallels Client" is available for download on the authors site.
Kidsnapper is a Free Portable Remote Screen Capture software that can be used to send screenshots (snapshots) to a web browser running on a remote computer. Kidsnapper is good for showing things to people remotely (coworkers or customers at a remote location).
Brynhildr formerly ZeroRemote; is a Free Portable Remote Desktop Program for Windows which includes both client and server in one package. This easy to use free remote desktop software allows you to remotely control another computer from a USB flash drive, on the go - no matter where you are.