The Ontario, Canada Provincial Parks system has integrated the Google Maps service with their park listings tool. After locating a provincial park based on your requirements the results page features a map link that plots the specific park you've chosen. They have also integrated the Google Maps directions feature as well, but since some of the parks are in very remote locations this can of limited use.
Here is an example using the Provincial Park I grew up minutes from:
..This is the second Canadian-based mashup I've seen this week. Since I'm a bit short on Canadian listings, if any of you know of more that are Canadian-based Google Maps mashups or integrations, please post them in the comments section! :)
[thanks to the creator of TheStar GMap overlay for this one!]