Despite the dynamic and interactive nature of the language underlying applets, the typical applet still performs a fixed set of operations. Users cannot easily reconfigure such a system to perform "what if" experiments or gather statistical or timing information for an experiment. Thus, while Java and the Web support dynamic interactions and enable exciting capabilities in educational software, few applications built on them exploit these capabilities. The article describes CSLab, a proof-of-concept prototype of a simulation environment that is easy to use, dynamic, and Web-accessible. It is designed from the ground up to exploit the inherent dynamic behavior of Java and the Web and to let end users capitalize on this behavior. The authors' goal was to build a framework within which to create, configure, and execute experiments, but instead of the physical sciences they focused on experimental algorithmics. The CSLab executable is a framework for creating various simulation experiments using available modules.