Obama readies annual stand-up routine for DC's A-list

Once a year, the world's most powerful man becomes a punching bag for laughs, even throwing a few jabs at himself. On Saturday, US President Barack Obama will endure this light-hearted evisceration for the seventh time, appearing at the White House Correspondents' Association annual dinner. A spring ritual in Washington, anybody who is anybody in US public life shows up to eat, drink, schmooze and be seen. It all unfolds before an audience of 2,000-plus journalists, politicians and Hol