Soot is a Java optimization framework. It provides three intermediate representations for analyzing and transforming Java bytecode: baf, a streamlined representation of bytecode which is simple to manipulate; jimple, a typed 3-address intermediate representation suitable for optimization; and grimp, an aggregated version of Jimple suitable for decompilation and code inspection. Soot can be used as a stand alone tool to optimize or inspect class files and a framework to develop optimizations or transformations on Java bytecode.
XTemplate is a template engine for PHP which allows you to store your HTML code apart from your PHP code. It has many useful features such as nested blocks and various kinds of variable interpolation, and yet the code is very short and very optimized. It includes several examples and was written with an attempt at being easy to understand. The basic syntax is from FastTemplate and QuickTemplate but the entire class was written from scratch without code from other template engines.
Ivf++ (Interactive Visualization Framework) is a simple OpenGL/GLUT-based C++ visualization framework. Its main goal is to create a foundation of classes that can be extended in simple ways. It also encapsulates the GLUT event model in a set of easy-to-use classes (based on the GlutMaster classes), so a simple GUI can be built quickly. It can be used together with other GUI libraries using provided widgets.