I want to draw an interactive rectangle on screen which should be used as the extent for clipping geometry for raster datasets. Any suggestion?
Actually, if you are doing this witin ArcMap and you have a feature layer (that overlays properly) and has detailed enough features you can select that will serve to define the extent you want to clip, then Clip from the Raster Processing toolset (Data Management >> Raster >> Raster Processing >> Clip [v10]) has an option:
Use Input Features for Clipping Geometry
...that will essentially use the selected features extent as the clipping boundary. Pretty convenient provided your fc has existing features you can select (e.g. by rectangle w/ select tool) whose combined extent envelope matches the extent you wish to clip by.....unfortunately, this is not always the case. This is the closest system provided means without going the route of making a custom tool.