Free Logo Interpreters
LIOGO is a Logo compiler for .NET. Logo is an interactive programming language mainly used for learning. Compiles to EXE or DLL.
StarLogo TNG is The Next Generation of StarLogo modeling and simulation software. While this version holds true to the premise of StarLogo as a tool to create and understand simulations of complex systems, it also brings with it several advances - 3D graphics and sound, a blocks-based programming interface, and keyboard input - that make it a great tool for programming educational video games.
NetLogo is a programmable modeling environment for simulating natural and social phenomena. It was authored by Uri Wilensky in 1999 and has been in continuous development ever since at the Center for Connected Learning and Computer-Based Modeling.
Elica is a Logo implementation that goes beyond the flat turtle graphics with its 3D animation of user-programmable objects.
Berkeley Logo is a freeware interpreter complete with c source code written by Brian Harvey. His site also has some sample chapter from Logo books that he wrote.
TKTSLogo is a "Traditional" Logo interpreter. The beginner will want to start with controlling the turtle whereas the expert can work happily without any graphics at all. For Windows 98, 98se, ME, 2000 and XP.