Check the video, and then follow below for some background.

The New York Times on Hillary’s cackle:

It was January 2005, and Senator Hillary Rodham Clinton had just finished a solemn speech about abortion rights — urging all sides to find “common ground” on the issue, and referring to abortion as “a sad, even tragic choice to many, many women.”

Stepping offstage, she took questions from reporters, and found herself being grilled about whether she was moderating her own pro-choice position. And suddenly it happened: Mrs. Clinton let loose a hearty belly laugh that lasted a few seconds. Reporters glanced at one another as if we’d missed the joke.

This was my first close encounter with Senator Clinton, and with The Cackle. At that moment, the laugh seemed like the equivalent of an eye-roll — she felt she was being nit-picked, so she shamed her inquisitors by chuckling at them (or their queries).

Follow here for the entire story @ NYTimes.com

As for Stewie and Brian? That clip is from one of the only funny episodes of Family Guy post-return to Fox. Wikipedia:

Cheeky Bastard: A sitcom staring Stewie and Brian as bickering roommates, in a style akin to The Odd Couple. Stewie also provides the show’s laugh track, contrary to the claim that it was filmed in front of a “live studio audience.”