Well, you can pretty much do everything!! Catch a live play, listen to a great band of any type, have a great meal, shop your brains out. And the next day, do it all again!
..and don't listen to Luvian or pritchke, they don't get out much
..now, Quebec City is a different story..
I lived in Ottawa for 23 years. It's beautiful and not too big and you'll never find a cleaner city.