Here is some RTF text (bold Verdana font, in red, now blue italics)

Any OLE content can be embedded, any at all.  Here are a few examples.

Bitmaps are easy.  Here is a familiar .gif-formatted image.  

Windows media (.wmv file).  Remarkable.

An Excel spreadsheet.  Double-click to open it in Excel and change its values.

A PowerPoint presentation.  Double-click it and it opens for a full-screen presentation.