My 18 month old son received the Fill and Dump Wagon as gift this year and it has become one of his favorite toys. The toys consists of a small red wagon with forty large plastic interlocking blocks inside. Think BIG legos. We have some of the duplo sized legos, that my son plays with a lot, but these blocks are much easier for him to manipulate. He can easily put them together and pull them apart without help. These hold his attention longer because he can do them himself and doesn't get frustrated.
The blocks are fun for building, but the wagon is great too. Besides being a place to store the blocks, it's also fun to pull around the house. My son fills it up with stuffed animals and pulls it all over the place. The wheels aren't completely level, so 2 of them don't roll over our hard floors. Although this doesn't make the wagon any harder to pull. It just drags a little, but it works great on the carpeted areas of our house. This is a toy that we'll have fun with for a long time!