In the British government, the Prime Minister appears before the House of Commons every week to answer questions from the MPs about current governmental activity. According to Parliament's website:

Prime Minister's question time usually starts with a routine question from an MP about the Prime Minister's engagements. Following the answer, the MP then raises a particular issue, often one of current political significance....Exchanges may become heated, and this is often the spectacle presented on television (on C-SPAN in the US).

Typical British understatement. A typical "heated exchange" is a vicious verbal-sparring match that goes something like this:

MP: {snotty question about British politics incomprehensible to outsiders}
Members of the Opposition: AAAAAAAARRRRR! BAWWWWWHAWWHAWWHAWW! Heah, heah, heah!
PM: {snide, equally incomprehensible reply}
Members of the PM's Party: AH-HAAAAAA! Heah, heah, heah!

Some PMs have been quite good at Prime Minister's Questions. Whatever else you might think about her, Margaret Thatcher was perfectly capable of thinking on her feet and burning the ears off any MP who questioned her. John Major, however, couldn't handle it to save his life and tended to dither and fumble his way through the half-hour.

The US Government has no comparable event, which is a pity; one wonders how some American presidents would have handled it. Bill Clinton and Ronald Reagan could probably weasel their way through it, but the dysphasic Dubya and his dad would be squashed like bugs. For a good ol' knockdown, drag-em-out battle, you'd probably want a former mayor of New York City like Rudolph Giuliani or Ed Koch.