TightVNC Portable is a popular open source free and portable VNC Viewer that can be stored and run from a USB flash drive. Virtual Network Computing or (VNC) enables a user to view the desktop of a remote machine and control it with a the mouse and keyboard from a local machine as if you were sitting right in front of the remote computer.
TeamViewer Portable is a popular all in one (server and client) remote desktop program. This standalone RDP can be used for desktop remote control and desktop sharing.
RealVNC offers a free edition of their popular portable VNC viewer that can be stored and run from a USB device. Virtual Network Computing enables a user to remotely control any machine that is running a VNC Server.
Brynhildr formerly Zero Remote; 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.
MobaXterm Portable is software that provides a terminal emulator, SSH client, and X11 server in a single portable executable. It is designed for remote access to Unix/Linux systems, but can also be used for local terminal emulation.
ShowMyPC; A Free Portable VNC Server and Viewer all in one. This remote desktop sharing software allows for remote PC access, screen sharing, and remote support.
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.
ChrisControl is a Portable RDP + VNC Remote Control Tool. It can be used to test if a remote system is running Virtual Network Computing or Remote Desktop Protocol services via a given Host Name or IP address.
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. It is good for showing things to people remotely (coworkers or customers at a remote location).
MultiVNC is a cross platform multicast enabled portable VNC viewer. It can be used for stand alone VNC (Virtual Network Computing) to remotely connect to VNC Servers allowing you to access and share remote desktops on platforms that are running Windows, Linux, Unix, or Mac OS X.