Used in most flavours (embedded C, desktop apps, console apps, distributed programs, GNU libraries, Windows libraries, OpenGL, etc.) and at various jobs (example: the flight-simulation harness at cueSim, and the set-top box software at Sony Semiconductor
Object oriented techniques, test-first development, introspective self-documenting code, scripting support and plugins
Would like to learn. Started using for some small projects, including Python/QT GUI toolkit, and for using the Faces project planning software
Used for creating test-harness software at Sony Semiconductor, and used for text-analysis, networking, and even some GUI software since. I wrote most of the WikiBooks' book on Perl
Used Javascript to generate dynamic web-pages, games, calendars, image effects, etc.
Used to write a serial-port communications client using MFC, for serving software updates to embedded microcontrollers
Used 2D aspects of OpenGL for maps and associated user-interface design, including OpenIL images, transparencies, scissor functions etc.
Used for flight simulation sounds - see the projects page
Written graphics tools, file tools, network tools, and database programming, with many of the programs available on this website
Link to some of my Visual Basic software
Starting to learn some of:
Programmed PIC microcontrollers at home for a hobby, developed Z180 assembler software at university, and used embedded C (and a little ARM7 assembly-language) at work