I can top that. I bought up the mapping information for my home suburb (Richmond in NW Sydney) and immediately noted something interesting...
That long road linking William Cox Drive with Chapel Street does not exist! (Click here for the Google Maps URL) There is a private driveway for a small portion of that length, but the rest is pure imagination. These road overlays are not yet incorporated into Google Earth yet, as they are in other locations, so for now you've got to go to the browser-based site to see this.I think what has happened is that they must be creating their mapping data from aerial photography and where a line of trees may or may not obscure a road, they've just put the line in. It also shows that Google aren't just copying copyrighted information from the Gregory's or UBD guide, because it's well known that such cartographers put deliberate mistakes into their maps to catch copiers.
If an error like this became apparent on the first thing I looked at, then I can only assume that such errors are endemic. What's missing of course is a mechanism for correction. How do people with greater local knowledge get such bugs fixed?