Parking is expensive in the on-site underground lot. Try one of the nearby lots with a flat rate. National Gallery of Canada , Ottawa. The admission is FREE, except for special exhibitions. Once inside the gallery, you were not required to leave when the next group entered, but the whole exhibit was easily viewed within the alloted time.
Parking problems apply here, too.
Don't risk a parking ticket at any time. Still, it's worth the trek. If you are really not up to manoeuvering the streets, park your car at a shopping centre and take a cab or bus. Shopping centre parking is free, the buses are right there, or the cabs can be interesting. The Art Gallery of Ontario.