Displaying Code On Webpage

Is there a popular plugin/solution to displaying code (HTML, CSS, JavaScript) on a webpage with line numbers and copy/paste capabilities?

I feel like I see this functionality on a lot of blogs and so I’m hoping someone here will tell me that I can easily download a library to handle this for me. I suppose it wouldn’t be too difficult to write from scratch…but I’m sure someone has published this somewhere.

Also, I’m not using any blogging software, so if its a plugin for a blog then I won’t be able to use it - I’m looking for a standalone solution.

Thanks.