It is possible to embed all kinds of things on a wiki page. Check out http://www.wikidot.com/doc:embedding for several examples.
To display Google docs, we can use the iframe tag. It will look something like this:
[[iframe http://docs.google.com/pub?key=... width="100%" height="500"]]So we need to specify a link/URL (which I've truncated here with …), a width and a height. How do we get the URL, you ask? Just create a new Google doc (or open an existing one), click the "Share" button in the top-right corner, and then click "Get the link to share". You will see a popup window like the following:

You will want to check the first box so that anyone can view the document, and optionally check the second box if you also want anyone to be able to edit it (by anyone, I mean anyone who knows the link — i.e. anyone who visits the wiki). Finally, you need to copy the link, click "Save & Close", then paste the link into your wiki code.
The procedure is much the same for a Google spreadsheet, except that there is a little extra work if you would like to enable editing. Essentially, one cannot edit an embedded spreadsheet directly on a wiki page, but we can include an extra link that will open up the actual Google spreadsheet editor.
Here's an example that's taken directly from our volunteer-opportunities page:
[[iframe http://spreadsheets.google.com/pub?key=tpZsx-U6CncTAlOFXMzS6Uw&output=html&widget=true width="100%" height="560" frameborder="0"]]
> **[*http://spreadsheets.google.com/ccc?key=tpZsx-U6CncTAlOFXMzS6Uw CLICK HERE TO EDIT THE SPREADSHEET]**
>> This will open the spreadsheet in a new window.
>> Note that changes are saved automatically, so you don't need to click File, Save, or anything like that.The second line in this block of code contains a link that the user can click in order to edit the spreadsheet. The link/URL is the same as the one in the iframe tag, except that we removed everything that appears after the first ampersand (&) sign, as it's not needed here. The last two lines just display some extra information to the user.
Here's the result:
CLICK HERE TO EDIT THE SPREADSHEET
This will open the spreadsheet in a new window.
Note that changes are saved automatically, so you don't need to click File, Save, or anything like that.
That's it! Please post any questions that you may have in this discussion forum thread.