I come from a lisp background where I could type in snippets to the command line while coding, to make sure I get a small chunk of code correct the first time. Its great for testing string formatting, simple math calls, etc without having to recompile a whole project to test small changes.
Is there a feature or add-in in visual studio 2010 to get this type of functionality, say like a watch window that runs when you aren’t actually executing the program?
You can abuse the Intermediate window to evaluate things (in debug mode). However, i’d suggest LinqPad it has basic code execution on the fly.