Re: Coolness aside
There is very limited subset of PostScript function which can be used directly in PDF, but that doesn't use a PostScript interpreter. Type 1 fonts can be embedded and they do require a PostScript interpreter, but that's not part of PDF - TrueType fonts can be embedded too, but you wouldn't say PDF "contained" a TrueType interpreter. And you can also attach any type of file to a PDF as a binary blob - PostScript, an .EXE file, whatever - but it's just an array of bytes, and isn't executed.
Yes, some PDF readers can open other file types like PostScript, JPEG, TIFF - GhostScript and Acrobat being the obvious ones - but that's nothing to do with PDF.
There is, categorically, no way to execute PostScript inside a PDF. It used to be possible in theory ("PostScript XObject") but was deprecated by 2001, and I'm fairly sure it hasn't been part of any implementation for many years. I have never seen such a file, and I've been debugging PDF files since the late nineties. If you've got one, post a link here - I'd genuinely love to see it.
There's a surprising (to me) amount of confusion here, so I'm banging on about it to clear this up. PDF is not PostScript and does not contain PostScript. It was certainly inspired by PostScript but it doesn't have a stack and define functions. PDF is not a language, it is a document format. Of course there are implementation bugs - older versions of Ghostscript were recently found to allow file-system operations in the Type 1 font implementation, for example - but those are bugs, not by design.