+1 on eating Lebanese food. And the Byward Market is a good place to pick up picnic fixings, or for somewhat-spendy restaurants.
Aside from that, it's a pretty good city for recreational bike riding. If you can find a decent rental, you might want to head out to Gatineau Park, for the rare fun of riding on a paved trail through actual forest-y forest.
And because it's the capital, it has decent museums (national gallery, history, war).
[True story: My son once asked me, "How long did we live in Ottawa?" I said, "Seven years." He said, "What did you do, break a mirror?"]