As conference warm-ups go, there is nothing much better than a stunning by-election win.
By John Andrew
BBC local government correspondent
It could be that the biggest problem that the Liberal Democrats have next week is stopping the Brent East victory going to their heads.
Charles Kennedy will not get carried away
But it is not Charles Kennedy's style to be too triumphalistric and there is plenty more to talk about in Brighton.
Don't expect the Young Libs though to be welcome visitors at the Royal Pavilion.Their early bit of mischief at the conference is a motion on abolishing the monarchy and replacing the Queen with an elected head of state.
Shrewdly perhaps, the leader has taken a relaxed view of this - seeing it as alllowing the youth wing to let off steam in a similar fashion to previous party debates on legalising hard drugs and giving 16-year-olds access to pornography.
But it is a risk, since if passed by conference it will become party policy, even if the rules allow the party leadership not to include it in the next manifesto.
Other motions for debate include a ban on smacking children by removing the justification of "reasonable chastisement" and on scrapping the increasingly unpopular council tax and replacing it with a local income tax, something which is already party policy.
Delegates will also discuss doing more to protect against terrorism by appointing a senior cabinet minister to look after homeland security. It is all meaty stuff, but some may ask where the "big idea" for the next election is?
The party has already dropped the one policy which most voters could identify as theirs - the proposal for a penny on income tax to fund education.
Instead Charles Kennedy is offering the less sexy route of reshaping and slimming down central government and ploughing back savings into frontline services.
For a penny on income tax, voters should now read "1% off government spending".
Not so catchy perhaps, but in shying away from talk of income tax rises the Lib Dems are only folllowing the two other main parties, who have promised no increases in the tax in the last two elections.
When Charles Kennedy addresses the conference on Thursday, he will have plenty to celebrate.
Sara Teather's Brent East win is up there with Orpington in 1962 - for the old Liberal Party - and Eastbourne in 1990 on the list of great by-election wins.
With 54 MPs, Charles Kennedy has more members than any third party since 1929.
And his party's share of the vote in last year's local elections - around 30% - was its highest ever.
The biggest challenge now though is to sustain that position and build on it.
With Tony Blair in his roughest patch yet and the Conservative leader still fighting hard to prove his effectiveness it's been easier for the Lib Dems to come through the middle. That may not last.