PEBL is a Free psychology software for creating experiments. It Allows you to design your own experiments or use ready-made ones. It Lets you exchange experiments freely without license or charge.
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 available at http://pebl.sf.net.
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.