Complex sentence: Marge is overjoyed, and in gratitude for receiving this early Christmas gift, gives Bart his--the new game that a store salesman told her "all the kids want", the golf simulator "Lee Carvallo's Putting Challenge".
Split into simpler sentences: Marge is overjoyed, and in gratitude for receiving this early Christmas gift. She gives Bart his present, the golf simulator video game "Lee Carvallo's Putting Challenge".