(CNN) -- After Cleggmania, the "bigotgate" gaffe and the first-ever candidate debates, the Big Day is almost here.
Wednesday is the final day of campaigning before the United Kingdom goes to vote in the closest general election in nearly two decades.
The three main contenders would be well-advised to shake hands and kiss babies until the final hours. According to a new poll from ComRes, more than one out of three voters say they could still change their mind about which party to back.
The general elections of 2001 and 2005 recorded turnouts of less than 60 percent and 61 percent respectively -- the second- and third-worst showings since 1900, the UK's Economic and Social Research Council said.
But in the age of spin -- where everything is so carefully controlled by political puppetmasters -- a series of surprising events this year have set the UK political landscape alight and created an air of excitement around the election not seen in years.
The UK's electoral commission said 500,000 registration forms were downloaded from its website before the deadline on April 26, while a further 50,000 calls were made to its registration hotline. Some 40 percent of those interested were aged 18 to 24, the commission said.
The Conservatives, led by David Cameron, have led opinion polls for much of the past year.
Cameron has spent more than four years tipped as a prime-minister-in-waiting, a period he's called "the longest job interview in the world."
He is credited by his supporters with rehabilitating his center-right party after three successive defeats.
The Conservatives need to gain more than 100 additional seats -- almost a 7 percent landslide -- to secure a winning majority in the House of Commons.
Cameron's rival, Prime Minister Gordon Brown, is fighting to stay at Downing Street. If early opinion polls are right and Brown's Labour party loses power, his premiership will be the shortest in almost half a century.
Brown started successfully as prime minister: He handled the attempted terrorist attacks in London and Glasgow well, but his premiership went downhill when he ducked a widely expected general election in 2007 that would have given him his own mandate. Brown was never elected by voters as he took over mid-term from Blair.
The political mood shifted, and Labour has trailed in the opinion polls ever since.
The economic crisis hardly helped.
The country has massive debts; it is struggling out of recession and a series of industrial disputes is reviving memories of the "Winter of Discontent" that helped bring down the last Labour government in 1979.
On the international front, the military is fighting an unpopular war against the Taliban in Afghanistan. More than 280 British forces have been killed since 2001 and an opinion poll conducted in February found only 53 percent of Britons said they had a clear idea of what the war is about.
Adding to Brown's woes is the continuing criticism over a campaign gaffe dubbed "Bigotgate."
During a recent campaign stop, a 65-year-old woman -- calling herself a lifelong Labour supporter -- asked Brown about immigration and "all these Eastern Europeans coming in."
After ending the conversation with the woman, Brown got into his car and, while still wearing a radio microphone, said to an aide: "That was a disaster."
"She was just a sort of bigoted woman," he added, not realizing his comments could be publicly heard.
He has been apologizing since.
Then there is the "third force" of UK politics -- the Liberal Democrats, which for years has been an also-ran in British elections.
Its leader Nick Clegg -- a lawmaker for all of five years -- is riding high in the polls on the back of confident performances in the first-ever debates between party leaders during an election.
Perhaps unprepared for how well Clegg would play on television or how skillfully he would exploit voter anger at the two big parties, Brown and Cameron took his side often in the first debate in mid-April.
"I agree with Nick," they said repeatedly. By the next morning, the phrase was everywhere: on posters, T-shirts, in newspapers, online and on television.
Quirks in the voting system make it very unlikely the Lib Dems will actually overtake either of the big parties in the number of lawmakers it sends to Westminster.
But the surge in support for the smaller party might deny the Conservatives a majority.
A major possibility: a "hung parliament," when no single party reaches the minimum number of seats -- 326 -- to enjoy a governing majority.
Without a majority in parliament, a government becomes dependent on MPs -- or lawmakers -- from other parties to get its program voted through the House of Commons, the chamber that passes laws and legislation.
That could mean Cameron or Brown will need Clegg's support to form a government.
But after weeks of surging popularity, this week brought bad news for Clegg.
The ComRes poll found that Lib Dem voters are significantly more likely than Labour or Conservative backers to say they might switch at the last minute.
That might help explain a sudden drop in support for the Lib Dems in the latest poll by YouGov: it plunged to 24 percent, while the Conservatives are at 35 percent and Labour at 30 percent.