Canberra as a city is quite... small? If you want to visit a city that is like Melbourne or Sydney; then this is not the city for you. Go to Melbourne or Sydney instead, "for this is Canberrrrra"
The city itself is pretty; it's filled with many buildings and a few points of interest such as the parliament building, various museums and a war memorial.
If you're looking for cool hikes and activities then you will surely find yourself hiking Mt Ainslie, attempting to trek around Lake Burley Griffin and trying not to die from heat exhaustion/dehydration. (Totally worth it for the views though)
And if it's food and drink you're after, look no further than Pàtissez in Manuka; where you can experience the world famous 'Freakshakes'.
But the sheer highlight of this city has to be the hilarious people who live in the YHA hostel. On day 2 of my visit to Canberra I came across a lady in a pink nighty. I was on my way to the bathroom in the evening when she asked me where the pizza and pool was (odd combination, but ok). I told her that I didn't know but that I'd ask someone. I eventually found out and then told her. She seemed to be confused and had apparently forgotten how she had gotten to the second floor. So, I directed her to the lift. After a minute or so, I started to worry so I decided to head down to the kitchen to find her.... Turns out that she had given up on the pizza and pool idea and had decided to harass JD to make her a cup of tea.
Cue meeting JD: (normal guy) JD had been put into a room with a crazy guy who liked to sit in the dark with a guitar, had booked 2 beds in the room for himself, occasionally strummed his guitar for effect and had asked JD if he wanted a Thai massage. It was safe to say that JD moved rooms soon after.
Day 3: I wake up to new people in my room and we start exchanging stories. I decide to tell them about the lady in the pink nighty and JD's ordeal. We laugh... and then the lock on the door rattles and in walks the lady in the pink nighty. She chooses a bed, puts her stuff in a locker and walks back out. We laugh. She's here to stay...
Welcome to Canberra!