We get the latest on the ash cloud drifting across Europe from Iceland's Mt. Evjafjallajokull, the resulting air traffic cancellations, and how experts are keeping a close eye on a neighboring volcano in Iceland that could erupt next. We speak to Adam Gabbatt with the Guardian newspaper in London who's been live blogging about the volcano.

Many of today's runners in the Boston Marathon are running for charity. The charity program was set up 22 years ago, partly to give runners a berth in the race, if they couldn't otherwise qualify. Dave McGillivray was one of the first charity runners. Now he's the Boston Marathon's Race Director. We speak to him and others about the program

Pope Benedict is marking the fifth anniversary of his papacy today, with the clergy sex abuse scandal as his backdrop. Yesterday, the pope expressed shame and sorrow to a group of men on the island of Malta who said they are victims of clerical sex abuse. Those words might not be enough in the pope's home country of Germany, where a quarter of the church's followers are contemplating leaving the faith. The BBC's Steve Rosenberg report.

April 19th has become the most significant day in the calendar for the right-wing patriot movement. It's the day the first shots were fired against the British in the Battle of Lexington and Concord in 1775. It's also the day in 1995 that Timothy Mcveigh, fueled by anti-government rage, bombed the federal building in Oklahoma City. He wanted to mark the anniversaries of the federal raids in Waco, Texas and Ruby Ridge, Idaho a few years before. Today, gun rights activitists hold two rallies in the nation's capital. We speak with Mark Potok, director of the Southern Poverty Law Center's Intelligence Project, who tracks extremist groups.

A report from the finish line of the 114th Boston Marathon, plus, a conversation with Lisa Rainsberger, the last American woman to win the race.

• Dntel, "Last Songs"
• Sonny Rollins, "Get Happy"
• Charles Mingus, "Pedal Point Blues"
• Nathan Milstein, "Bach: Sonatas and Partitas for Solo Violin"
• Peter Dixon, "Nagog Woods"
• Christian McBride, "Brother Mister"
• Steve Earle, "Transcendental Blues"