A free plugin that allows you to paste text in InDesign without formatting
Ctrl Attribute Strip is an InDesign plugin by Ctrl Publishing. Here is a brief description from the plugin’s creators:
CtrlAttributeStrip removes the format information from the text when performing cut and paste from applications that use formatted text, e.g. Microsoft Word. CtrlAttributeStrip does not handle tables and hyperlinks.
Download the plugin from Ctrl Publishing.

This is going to sound really crass, but who cares?
Really, is there a need for a plug-in that strips pasted text formatting when, most times, one wants formatting retained and, the rest of the time, stripping formatting during file import does the job?
This sounds very much like a client-ordered custom plug-in that the company decided to release in case someone else got use from it.
Thanks for bringing it to our attention, Elisabetta, but Ctrl should really try to address genuine needs.
DESIGNORATI
Most of the time I don’t want formatting in my word docs. This is not the most sophisticated plug-in, that’s true, considering there are easy paste and copy tricks you can use to get rid of formatting.
And this is a year old release by the way.