Board Thread:Support Requests - Designing Your Wiki/@comment-24078842-20131022030041/@comment-1158325-20131022061928

Well Jsteel beat me to it, but here's a little more step-by-step I had typed out:

While viewing the Google Doc, go to File -> Publish to the web. Choose the sheets and keep the checkbox checked; click "Start publishing"; choose "HTML to embed in a page" in the next dropdown; copy the code in the box at the bottom. Then go to your wiki, go to MediaWiki:Whatever, replacing "Whatever" with whatever you want to call the spreadsheet, and paste the code there. Then wherever you want to display the spreadsheet, put  (replacing with the name you chose). See Help:Verbatim for how this works. Let me know if you have any trouble, I haven't actually tried this myself.