the easiest way to get a nice looking google calendar onto your wiki, is to use the embed code that google provides.
So if you log into your calendar, in your calendar view click on settings for the calendar you want to embed. Then copy the code where it says "embed" that will be linked specifically to your calendar, and it looks great.
Just make sure to add the wiki embed codes (I tried to type them here, but then it searches for something to embed, heh) after the code that google gave you. It works perfect.