We recently took the Alexander Keiths brewery tour and really enjoyed it. The group we were with included several children, and they were not bored. The tour is not like other facts oriented "how it's made" type tours I've been on, it includes live actors in period costume, never out of character, taking you back in time to the days when Alexander Keith was building his business in Halifax in the 1800's. They do an amazing job, and the tour culminates in the "pub" where you get to sample two of the beers (or iced tea or lemonade if you're underage or just don't drink) and they sing songs, tell stories, etc. We were very pleasantly surprised.
You could spend 2 weeks in Halifax and not have time to do all that there is to do just in Halifax/Dartmouth.
I haven't been to the Citadel yet, they tell me that tour is a good 'en too, and there are guided and self guided historic walking tours of downtown Halifax.
There are guided tours of the Basilica during the summer (haven't been on one of those either, though I try to get to Mass there every friday afternoon! Should check out the tour some time, just for my own information)
I've also been on the Harbour hopper which is very very cheesy, but lots of fun too. I'm not sure it's worth the expense, BetRx could speak more to that (since she so graciously covered my admission when we went!) It's sometimes hard to be objective about the touristy stuff when you live here. (listen to me, like I'm a native Haligonian. pfft.)
And if you are in Cole Harbour to take a picture of that sign, then you are close enough to have lunch (or dinner) at one of my favourite places in Cole Harbour. Jamesons pub is a great little Irish pub, nice ambience, celtic music in the background, AMAZING food-the banana caramel desert thing is awesome-and live music on weekend evenings. I've actually never been there when they had a band playing so I can't speak to that, but I will sing homage to the pan seared scallop salad..mmmmmmm.
And BTW "scallop" rhymes with "trollop"
In the social order, I accept the bottom rung, until the wine is pouring and the Lord commands a song!