You can rotate pages,comments, images, and form fields but not context text.
Actually, you can. In Acrobat XI, at least, it can be done using the Edit Text & Images tool.
You select the tool and then click a text box on the page. Move the mouse to one of the corners of the box and stand close to it, but not exactly on it.
The mouse cursor will change to a rotation icon. Click and drag to rotate the box, and with it the text in it.