Today we rented bikes in Montreal through its Bixi bike rental program (Le reseau cyclable de Montreal). There are tons of bike racks and you just swipe your credit card and rent a bike. When you're done riding you park it back and the rack automatically locks, but you can take the bike out again with the same passcode whenever you want if it's still within your rental time.
My sister and I biked all around downtown Montreal, Parc la Fontaine and then up to the Parc du Mont-Royal, Montreal's little mountain. The city has incredible bike paths all over, so you feel safe and you're not competing with cars. It was just like when we were kids, except she could actually keep up with me now and was leading us. That's what happens with little sisters, they grow up and take charge.