 On February 12, 2009, he also appeared on "The Tonight Show with Jay Leno".Greven appeared a second time on "The Ellen DeGeneres Show" in April 2009 to promote his two new books, "How to Talk to Dads" and "How to Talk to Moms".Greven's first book, "How to Talk to Girls", started as an elementary school project and ended up on the "New York Times" best sellers list.