Mathnetics is an API for creating advanced, interactive, Web-based mathematical applications. It defines various important mathematical objects that are inter-related and on which many numerical calculations can be done. It also features rendering of 3D objects onto an SVG canvas (to do so, it includes certain utilities such as browser sniffing, DOM node selection, and DOM readiness detection), which is quite robust. A few basic 3D objects are given (Line, Sphere, Cube), but the user can define any 3D object desired as per the specification.
Metatrace is a C++ compile time ray tracer. It is mostly a nice gadget to test compiler performance and conformance (apart from the maximum recursion depth of 17), especially but not exclusively in the template and metaprogramming corner of C++0x.