While on “The Late Show,” Stephen Colbert told the story of accompanying his girlfriend to an interview for an internship for the show Source

David Letterman and Stephen Colbert shared the stage at the Ed Sullivan Theater on Tuesday night. Colbert is taking over for Letterman when the late-night TV host retires next year. Alison Harmelin caught up with fans outside the theater. Source

Police say a new drug, with nicknames like 25i, N-Bomb and Smiles, is a dangerous narcotic that first gives the user a euphoric feeling, but then can cause disorientation and violent behavior. In the most dangerous cases, the drug causes a rapid heart rate which has led to deaths. WUSA’s Peggy Fox reports. Source

New technology is allowing more women to pause their biological clocks and start a family whenever they’re ready. Emma Rosenblum is the author of this week’s Bloomberg BusinessWeek cover story, “Freeze Your Eggs, Free Your Career.” She joins Dr. Jamie Grifo, program director of the NYU Langone Fertility Center, to discuss this trend. Source

Daily health headlines: New study looks at the consequences of getting a false positive mammogram, a link between dietary fats and colon cancer, plus more top stories. Source

Investigators say the ring, in Haverford, Pa., was selling marijuana, ecstasy and cocaine to local high school and college students Source

Dr. Holly Phillips, CBS News Medical Contributor, joins UTTM to discuss seasonal allergies and a wave of flu cases hitting the northeast. Source

Pamela Falk, CBS News Foreign Affairs Analyst, discusses Vice President Biden’s arrival in Ukraine to lend US support. Source

Many Americans expressed doubts about scientific evidence on the Big Bang, evolution and climate change in a new Associated Press survey. One of the nation’s leading physicists and science educators, Brian Greene of Columbia University, spoke with CBS News about the findings. Source

The 2014 Boston Marathon winner, Meb Keflezighi, was a spectator when bombs rang out at last year’s race. He tells Jeff Glor he took motivation from the attacks and wrote the names of those who died on the four corners of his bib. Many runners dedicated the race to those affected by the bombings, and many survivors took to the course to reclaim the marathon; John Odom was waiting to cheer on his daughter when the first bomb went off at the Boston Marathon’s finish line last year. He suffered major nerve damage in both his legs, but as Elaine Quijano reports, this year’s race was a day he was determined not to miss. Source