I've just found out that in Word 2013 and Excel 2013 there is a quick way to access, from keyboard, all the "Paste Special" options. In the following examples it is just shown how to paste as text (without pasting the formats).
###Word 2013:
Word 2013:
After having copied something go where you want to paste it (without pasting the format). CTRL+V (it will temporarily paste the format too) then CTRL (push and release the control key) then T (the last T means "keep text only").
###Excel 2013:
Excel 2013:
After having copied something go where you want to paste it (without pasting the format). CTRL+V (it will temporarily paste the format too) then CTRL (push and release the control key) then V (the last V means "paste Values").
It's important that the second CTRL key is released before typing the last letter.
This method requires just 4 keyboard hits, no macros and no use of the mouse in a dialog window.