I observed that the kids really enjoy the "Practical Life" materials in the Montessori Classroom. These materials are specially made for kids but include everyday life activities and objects. For example there is a tray with a cutting board, fruit cutter, a bowl and a small plastic apron. The child cuts fruit and then shares it with the rest of the class as a snack. It develops all three: sensory-motor, social and cognitive skills.
At this age, little children enjoy every day activities and everyday objects. Pots and pans in the kitchen are very attractive and baking cookies is a great activity for older kids. I think interacting with house hold items (safe ones of course!) instead of toys helps their involvement with the environment and facilitate the exploration of the real world.