Donald Trump May 19, 2015 3:40 am WATCH: Jimmy Fallon Thanks David Letterman Jimmy Fallon takes some time to pay tribute to “Late Show” host David Letterman and wish him well on his retirement. US & World Videos 8:39 Gina Rodriguez gushes 0ver motherhood with son Charlie 2:22 Scarlett Johansson and Colin Jost have date night at White House Correspondents' dinner 2:09 President of MIT calls for shutting down pro-Palestinian encampments 3:57 Pleasant Sunday despite morning showers 1:00 Three dead in apparent murder-suicide in Lowell