Anything can happen in the next half hour!
One of the best TV series hook lines ever was the famous opening to Stingray: "Marineville I am calling Battlestations - anything can happen in the next half hour". Well that's how this election is beginning to look. In fact if copyright allowed it, I would gladly replace Newsnight's opening titles with this.
As the media gets back to its 24-hour rolling frenzy after the long weekend this morning it's worth trying to summarise what's happened since last Thursday - because I think it will be seen as significant with hindsight, and makes the whole situation unpredictable.
First the Guardian came out in support of the Libdems. Defying expectations - and calls from within the editorial team - for a simple tactical voting line, the self-designated "global voice for liberalism" adopted a capital-L - and that could presage bigger changes on the centre-left of British politics. This created a momentum within the Labour party that has resulted in parallel coded calls for tactical voting this morning, from Peter Hain, Ed Balls and Lord Adonis.
Then there emerged the "plot against Gordon" briefings. Patrick Hennessey of the Telegraph summarised a lot of what's being said in background: if Labour has to approach the Libdems on Friday morning for a coalition you would see simultaneous moves to replace the leadership, with the usual camps lining up - David Miliband (visionary neo-Blairite) versus Alan Johnson (affable stop-gap). Veteran Labour journalist Will Hutton called for Nick Clegg to become PM.
Gordon Brown, who had only decided to speak to the London Citizens' conference on Friday, turned up to it on Monday and delivered a left-leaning, barnstorming speech to an avalanche of applause and a lot of surprised Twittering by labour folks along the lines of "who is this guy who looks like Gordon?"
It was not just the Guardian's move that focused minds within the Labour hierarchy: it was the emergence of the "momentum" theme in media coverage of the Conservatives. Conservative internal polling has, for several days, been consistent with last night's Ipsos-Mori marginals poll - which is that they have a differential 7% swing in the marginals that could give them a tiny commons majority: but only as long as they don't lose seats to the Libdems.
This poll is actually really interesting. Remembering it is a poll of marginals, it states that: about 11% of people have already switched votes during the campaign; about a third are open to changing their minds; and the Libdem vote is softest followed by Labour. In short it confirms that there are too many variables to call it.
Meanwhile Conservative spin-doctors are working overtime to create a "quiet march to Downing Street" momentum.
David Cameron broke with tradition and began to spell out some of the immediate actions he would take - and began to put out messages of reassurance on protecting front line services. I read all of this as political ammunition for a push into the "red" end of the Labour-Tory marginal list, with an emollient message to areas where he knows there is residual mistrust for the Conservatives.
Within the Libdems there are two scenarios emerging. The first - which their campaign evidence seems to encourage - is that they might come second (obviously they want to come first) in the popular vote. If this happens it will turn Cleggmania into a much bigger political phenomenon and you will begin to see post-election re-alignments in British poltics. The second scenario is they get squeezed in the last few days but still emerge with somewhere between 70 and 100 seats and become instantly kingmakers in a hung parliament.
Interestingly the Libdems are still struggling to understand where their surge of support is coming from: they are getting mass sign ups to all Clegg's public meetings; are recruiting massively online and raising money ditto. Anecdotal evidence from party workers suggests quite a lot of this is happening within Labour areas and from within - yes, our old friend "Mosaic Group E" - young, urban, transient and trendy. There are some within the party who believe this puts them at the head of a true, Obama-style postmodern demographic swing. Others see it simply as a reward for a lifetime of thankless hard work.
With all the newspapers now indicating their voting preference, and rising calls for tactical voting between Labour and the Libdems, all three party machines believe there is, if not "all to play for", then something to play for. Their relentless campaign schedules matter; as does the crucial battle for domination in the broadcast media. It will be relentless for 48 hours now.
Oh and the bond markets have decided to open at 1am on Friday so that, before 90% of the votes are counted, the international markets can get their retaliation in first. There's no Newsnight on Thursday night but I will be out, armed with my earpiece and the idiot's guide to 10-year gilt spreads, at a constituency count that I am told will finish at 5am.
By then it will be all over bar the shouting - but for once I think we can guarantee there will be shouting, and not all of it ecstatic. Keep your finger on the refresh button and follow me on Twitter.