PEBL – Psychology Experiment Building Language
http://pebl.sourceforge.net/

This is the main website for the PEBL programming language and execution environment. PEBL is software for creating psychology experiments. PEBL offers a simple programming language tailor-made for creating and conducting many standard experiments. It is Free software, licensed under the GPL, with both the compiled executables and source code available without charge. PEBL is designed to be easily used on multiple computing platforms. Its current implementation uses the SDL as its implementation platform, which is also a cross-platform library that compiles natively under Win32, Linux, and Macintosh Operating Systems. PEBL is programmed primarily in C++ (although you do not need to know C++ to use PEBL), but also uses flex and bison (GNU versions of lex and yacc) to handle parsing. This has been added to World Wide Web Reference Subject Tracer™ Information Blog.