This is one of the 24 short pieces Tchaikovsky wrote for children. He picked up the idea from Schumann, who wrote Childhood Scenes, and credited his fellow composer by adding the sub-title 24 simple pieces a la Schumann.
It is a wonderful piece that we came to know when an arrangement for string quartet was played during a concert of the Borodin String Quartet (check out our blog).
Marlous Smit-Van den Hoven arranged the work for piano quartet in such a beautiful way that your audience will be asleep when you reach the final measure. If played right that is !
Parts and score in PDF (piano, violin 1 and 2, cello). See the first page of the score here!