Gelide is a configurable frontend which let you manage any kind of emulated system (arcade, console, PC, etc) letting you to catalog and launch any game from any existing emulator under GNU/Linux.
The Cell framework is a scalable server framework written in C#. It's original purpose is for MMOG emulation but can be easily adapted to other areas. The project includes a proof of concept rewrite of the DAoC emulator DOL.
qsh is a shell for any operating system. It is coded in java so it inherits the pros and cons of java. It is in a very nascent stage, but all the regular commands work: Directory navigation, file tasks etc.