In the warehouse part of the store they have these big flat carts, so you can load them up with boxes full of things that need to be assembled. These carts move in the same fashion and are ideal for lugging small toddlers on.
The warehouse is just like Costco or Homedepot with tons of big huge isles, just begging for someone to run up and down them. I had Ava and Seth hold onto the cart while I started to run at the beginning of an isle. As we picked up speed, I jumped up on the cart with one foot (the other served as an emergency break) and we'd glide down the isle, turning from side to side as I shifted my weight. I'm fairly certain I enjoyed this more than the kids, although I'm pretty sure they loved it. Ikea is rad. Don't believe me? Look up Ikea carts on youtube.