While debugging we can mouse over on an variable to look at the value or to explore further and we call this as DataTip. In Visual Studio 2010, we can stick DataTips to our code window and drag & drop to any location and the DataTip will hang there. This really facilitates the debugging process.
Run your application in debug mode and mouse over on the variable to pin and click the pin icon. To unpin, just click the unpin icon again in the debug mode.