PSHAW is a pseudo command prompt for accessing a machine remotely using only a Web browser. It cannot run interactive programs. It can only run programs that run, spit out text (or not), and then quit. There is a handy drop-down box of previously run commands. The page never reloads thanks to AJAX.
GreenT is a Linux terminal emulator written in C#. Its visibility can be toggled by a hotkey just like the consoles found in games. Additionally, it supports tabs like gnome-terminal. It uses gnome-terminal's settings for its configuration which it updates in real-time when changed in gnome-terminal.
WmConsole is a console server for Windows Mobile devices which listen over BlueTooth RFCOMM channels. It allows the user to interact with the device using a commandline interface from a Linux or Windows workstation. You need the QTTY Linux/Windows client to access a WmConsole server.
retty is a utlity that can attach to processes running on another terminal. This is useful, for example, when you run an application locally and then decide you want to use that running application from some remote location. You can run retty on it, do your work, and detach application back again. Its advantage over screen is that you don't have to run the processes on retty in advance.