YouTube makes it possible for teachers to capitalize on children's insatiable appetite for visually stimulating learning. Some of these videos attain "viral" status, getting passed on from person to person and by links on other sites. Not only are these popular videos viral, but developing one's own content and posting it for the world's access is infectious, even for latecomers to the educational technology scene. Also, incorporating YouTube into science lessons can energize your teaching and motivate students, too. In this article, the author shares some experiences and ideas for using this dynamic tool in the science classroom. (Contains 8 online resources.)