Late Show with David Letterman S15 E75 Kid Scientists, Natalie Portman, Kenna

"AMPTP President Nick Counter" and "Writers Guild Executive Director David Young" call a truce... and make out; in tonight's remote, Andy Kindler visits a toy convention; the latest Kid Scientist experiments from Naperville, IL include gravity-defying water and a crudely-built hovercraft; Kenna (featuring N.E.R.D.) performed "Say Goodbye to Love."