Part of what makes Cathy Fink and Marcy Marxer, the Indigo Girls of the kids" music circuit, so successful (their last five albums have all received Grammy notice) is an aversion to biting off more than they can chew. So it goes with Bon Appetit, which follows the Fink/Marxer formula by deftly dipping into a range of genres that includes swing, samba, and show tunes and brightly making their points. "Water," we"re told, is "like a washing machine/ It keeps the inside and the outside of your body clean." "Breakfast Power" rules, and germs have got to go. Bananas, potatoes, and big muscles also championed. In the end, thought, the track full of food jokes ("Why did the cookie go to the hospital? He felt crummy!") that takes the cake.(Winner of the 2004 Grammy for Children"s Music) --Tammy La Gorce