If you're not into building arcardes, here's 2 other ideas I really like:
|Since my tot loves trains, I had to feature this from apartment therapy.|
|Great box pulled toys featured at Made by Joel (image from their site)|
What have you made out of cardboard boxes? I want to know! Just the other day, we used one for a car, which I'm hoping we can decorate soon. Also, Tip Junkie has a round up of 32 ideas for your cardboard boxes.