OAFs often attend and support RASC star parties at the Carp branch of the Ottawa Library (next to the famous Diefenbunker). There is a large parking lot with room for scopes and visitors, on the top of a hill with good horizons. The library turns of the exterior lighting off for the events, and the sky is about as dark as you can get while still in the easily-accessible part of Ottawa.
Here is a Google map of the observing site.
Check out the RASC Carp Star Party Schedule for more information about the Carp library site and the potential dates for the star parties.