By Nick Assinder
Political correspondent, BBC News website
Once a week - it used to be twice before Tony Blair "modernised" it - MPs and politics watchers pack into the Commons or turn on their TVs to watch the modern equivalent of the Roman games, only more brutal.
Mr Brown's performance will leave a lasting impression
Prime ministers' questions is one of only three regular events that can still be guaranteed to get a big audience in the chamber, the budget and the Queen's speech being the other, albeit less gore-soaked, two.
So, us anoraks love watching PMQs and millions of words are written and spoken about it. But do these gladiatorial clashes add up to a row of beans in the wider political landscape?
The answer is, absolutely, unequivocally "yes". Quite a bit.
Yes, because the performance of a leader in question time can quickly determine the way he or she is perceived by MPs on all sides.
It also sends out a subliminal message to the public, via the media, about the party - if the leader is useless, the party must be useless as well.
That can lift backbenchers' morale, particularly for an opposition struggling to make its mark, or plunge them into further despair and, fatally, leadership plotting.
Most recently, the relative performances of ex-Tory leaders William Hague and Iain Duncan Smith are perfect examples of this.
Mr Hague was one of the best question time performers in recent memory. He regularly bested Tony Blair, usually with his flick-knife humour and ability to think on his feet.
Mr Hague's performances boosted morale
Virtually every week he gave his backbenchers reasons to be cheerful. Sadly for him, it never lasted long and he had to do it week after week.
His troops loved it, the politics observers enjoyed it and rated him highly and, as he has confessed himself, it had little effect on his electoral fortunes.
That is overly modest. Without those morale-boosting performances it is quite possible he would not have survived in the job long enough to find that out and his party may even have slumped further in the popularity stakes.
Mr Duncan Smith discovered that when it very rapidly emerged that he was, to put it politely, rubbish.
His performances were marked by a persistent frog in his throat, indecisiveness and a lack of the sort of humour that can get a leader off the question time ropes.
Watching him getting duffed up week after week was hugely dispiriting for his troops and seriously damaged his political health.
His MPs became desperate, fearing their leader was driving them towards extinction, and soon started plotting to remove him.
It wasn't entirely because of his question time performances - his other leadership qualities were widely seen as poor - but they contributed to his fall by adding to the public image of him as a man struggling to make an impact.
Mr Duncan Smith had unfortunate question times
And that is the other reason these sessions matter. Most people do not ever watch question time, but they read newspapers, watch TV and listen to the radio.
And it is the media, acting as a filter, which passes on the Commons view of a leader to the wider public.
None of this, of course, is to suggest question time is the only thing that matters. If that was the case Tony Blair would still be prime minister - he may have faced a more dangerous adversary in the shape of David Cameron, but he could easily match him and often beat him in the chamber.
Wider political movements ultimately decide the fortunes of a leader but his or her chances of holding onto their job and lifting their party's poll ratings is directly affected by the way he or she handles these sessions.
So, the first question time by a new prime minister or opposition leader is guaranteed to prove a huge draw.
And whose head lies on the carpet at the end of it really does matter. Up to a point.