Understanding a program?s behavior is of major importance for software developers, especially for program analysis activities. This fact is further pushed by ever more complex applications, increasing the demand for corresponding tool support. A solution to this problem is visualization, where the multi-dimensional relations of executing programs are expressed by some means of computer graphics or related multimedia techniques. An example for a truly human-centric environment is the activity tunnel, which tries to illustrate the activity of parallel programs during execution. The central metapher of this approach is to let the user "feel the program". This effect is aspired by 3-dimensional visualization and corresponding sound stimuli within the CAVE Virtual Reality environment.