... that would be nice, but the ROM already has a hard time funding itself, it definitely needs to charge a fee. I think that a Free Friday night is sufficient. It allows people who can't afford to pay to attend, while regular museum goers pay the fee to go at any other time.
If you're going out of your way to go on a Friday evening, then you must be hard on cash and deserve to go for free.
That said, it would be nice to have an equivalent of Washington in Canada. In D.C. all museums are free. I'm assuming they're fully funded by the US gov. Perhaps Ottawa's museums should all be funded by our federal government in an attempt to draw tourism to the city and afford all Canadians the chance to learn about Canadian history.