We live in a walkable part of city. In a park 1 block from our apartment, there are "baby trains" (small electric trains, on rubber wheels). They cost ~$2 for 5 minutes, plus 10 minutes of your kid screaming "want more". Subway in Almaty is $0.2 (for adult), unlimited time. So when my son was almost 2 y.o. and walked well, I decided to take him to the real subway instead of enduring that vulgarity (granted the station is just 2 blocks away). He loved it a lot. Shouted "too-too" when the train was departing. Wanted more and more. He couldn't speak then, so he was turning my head with his hands, to make me see the approaching train. Also, it was a hot sunny day of +35°C, but in subway, it was 10 degrees cooler. The first time, we travelled 1,5 hours strait, 2-3 stations back and forth. I sweated because I had to carry a rucksack and a 6 kg of folded stroller. But that was unforgettable.
I have a tip for you, if you ever visit Vienna, get a 24(48,72)hr unlimited ticket and spend some time on the subway (U-Bahn) with your kids, riding the various lines. The entire subway system has different trains (some more like street cars, some more like urban rail) and tracks run in underground tunnels, shallow trenches and over open ground.
Honestly, one of my favourite aspects of traveling is simply using the local mass transit.
Coming from a city where it's a particularly bad joke, it's still a novelty, and it provides such a different perspective on the city than "where can I park within orbit of $specific_destination"
I must add, I just remembered another story: I needed to make an overhead cupboard and a small closet, and found out there was no time to do this without kids nearby. So I did it together with the son. He was happy to press the button on the drill and to drive dowels with a toy hammer -- I drilled extra holes in the exercise board for him. We did it in several sessions, and afterwards he'd proudly tell people he made two closets.
Once I had to go to a DIY store on a weekend, and to free my wife from sitting with him, took him too. I knew we'd be fascinated, and indeed he was, studying everything for 2 hours.
