My girls LOOOOVE to dress up... and wear my makeup. Sometimes the urge comes upon them at inopportune times, and there's not a whole lot I can do about it (well, not without threatening their little lives, anyway).
The "Presto" (third movement) of Bach's Brandenburg Concerto No. 4 in G, BWV 1049, performed by The Academy of St. Martin in the Fields, and conducted by Sir Neville Marriner. Because it makes me happy, that's why.