Toys with interlocking pieces (ex. Mr. Potato Head).
Baby rattles and doors which have bells attached to them;
The halachas of opening food packages with letters, numbers, pictures.
Folding Garments on Shabbos, קיפול בגדים (Kipul Begadim). How הכנה (Hachana) Has to Do With Folding Garments on Shabbos;