Money Tip: If you have time to do more than 1 museum trip, then look for combo deals. Also, you are likely to get a better price online (if you can find a groupon, even better!) than landing there to buy them.
Canadian Museum of History
A personal favorite is the Canadian Museum of History, located in Gatineau across the Ottawa river overlooking the Parliament Hill - http://www.historymuseum.ca/
Complete Details - https://en.wikipedia.org/wiki/Canadian_Museum_of_History
It is the most visited Museum in Canada, and for good reason. It is setup with exhibits covering 20,000 years of human history. The flow of the museum is well established to give you a great transition through the times, starting from Totem Poles, Canoes, rafts, clothes, animals etc. They also have multiple exhibitions that go on during the year & it is nice place to visit more than once during a year.
They also have a CINE+ section which screens movies, so it could be worth your time to check what's playing.
Special Note: They also have a Children's museum section that could excite the young ones in your group!
Here are a few pics to showcase the place -
There was a special exhibit section on Emperor Napolean Bonaparte and here is a pic from the same -
On a side note: the sprawling riverside front is a great spring/summer retreat to just knock your shoes back and lay down, taking in the sights & sounds of the busy Ottawa Downtown area (It is also the location for special Fireworks that happens every year - find details in one of our other articles) 
Other Museums in Ottawa
Travel: Diefenbunker Museum in Ottawa
Travel: Canadian Aviation Space Museum in Ottawa
Travel: Canadian War Museum in Ottawa
