Pick your own Parliament
It's the fun game you can play at home. All you need is a little imagination and a well-worn anorak. Yes, folks, it's Pick your own Parliament.
Our esteemed politicians, of course, are masters at the game. They know that their party will win every single seat, everywhere. Adoring voters will flock to their side.
But, in the unlikely event that there are one or two sceptics out there yet to be convinced, preparations are under way for alternative scenarios: hung Parliament, coalition.
In Scotland, there is the added joy of calculating not just the UK winner but also the impact on cross-border politics.
In that regard, we now have a courageous constitutional doctrine from David McLetchie, the Scottish Conservatives campaign manager.
You'll find it as the splash in today's Scotsman. But Mr McLetchie actually made his comments on BBC Scotland's Politics Show.
The newspaper neglects to mention this: shortage of space, no doubt, or maybe they felt that the Beeb had featured enough in their pages, given the spread devoted to last night's Leaders Debate.
Anyway, no matter. Mr McLetchie said that he expected the Tories to win several seats in Scotland on the way to utter triumph.
But if they didn't? Would David Cameron lack a mandate in Scotland?
Mr McLetchie declined to countenance this but added: "The vast, overwhelming majority of Scots want to be part of Britain and they accept the judgement of the electorate as a whole and so David Cameron has a mandate to govern Britain of which Scotland is a part by the overwhelming choice of the overwhelming majority of Scots. That is the sheer logic of it."
Unsurprisingly, this "sheer logic" does not appeal to Alex Salmond. He argues that the Tories are, in effect, including support for other Unionist parties, Labour and the LibDems, within their proclaimed mandate.
Mr McLetchie, undoubtedly, would see things differently. In essence, he is confronting and countering a very old argument in Scottish politics.
Which is this: is there a distinct Scottish mandate at all? Remember 1992 when Labour expected to win - but lost. Then, Donald Dewar briefly flirted with the claim that the Tories lacked a mandate to govern Scotland.
Or consider the prolonged period when a succession of Tory leaders failed to oust Tony Blair. They started to deploy, more vigorously, the argument that there should be English votes on English issues, that somehow Labour's mandate in England was or might become questionable.
Successive Tory leaders, most notably David Cameron, came to the conclusion that this was not an argument which sat readily with support for the Union.
Mr Cameron chilled on this issue - while still pursuing the search for a solution to the West Lothian question within Westminster rules.
Ditto Donald Dewar in 1992. He quickly abandoned the mandate argument. If the Tories had no mandate to govern Scotland, then that involved fundamentally questioning the Union of Parliaments.
Within the rules of that Union, Mr McLetchie is absolutely right to stress that the mandate of the government at Westminster derives from Britain - or, rather, the UK - as a whole.
However, politics works by momentum, impression and voter tolerance as well as strict rules.
Could the Tories govern Scotland within the UK without a single Scottish seat? Yes. Would it be constitutionally and electorally challenging? Yes. Might it prompt Scots to question the Union settlement which had produced such an outcome? Perhaps.
The Tories, of course, point out that many domestic decisions are now devolved to Holyrood. The Parliament they opposed but now support now helps mitigate a potential problem which, to stress, they do not envisage arising.
Here's more fun in our guessing game. David Cameron is offering to show "respect" to the Scottish Government and First Minister.
From first principles, Alex Salmond would be tempted to respond positively, if cautiously. Remember that his strategy is to govern sensibly and consensuallly within the Union while, simultaneously, inviting the voters to go further towards fiscal autonomy and indepedendence.
However, Mr Salmond would find it exceptionally difficult to respond positively to that respect agenda if the Tories had very few, if any, MPs in Scotland. In such circumstances, the urge to decry the lack of a mandate in Scotland, viewed from a Nationalist perspective, might trump the prevailing consensual strategy.
None of this might happen, of course. Enjoy it while you can.