I encountered a few .pages files that were created on a Mac.
I am using a PC and my MacBook doesn't have Pages on it, so I was a bit stumped as to what to do (short of asking the author to export them as PDF).
Instead, here is a solution:
change the extension to .ZIP and open the files with Winzip or whatever. Inside there, you will find a folder called "QuickLook." Inside Quicklook, you will find a PDF of the .pages document! Bingo! Copy and paste the content, and you should be good to go.