Framework for making Windows applications that are one .exe file in AutoHotKey_L,C++,C#, VB.NET,Java,Groovy,Common Lisp,Nemerle,Ruby,Python,PHP,Lua,Tcl,Perl,Jint,S#,WSH VBScript,HTML/JavaScript/CSS,COM, PowerShell without compiling . For .NET 4.
Whatzit provides a system for using error and status conditions much more rich than the canonical 'zero means success, anything else is situational' mechanism. You can tell the severity of a condition and where it originated by looking at its value.