Apparently the tune is from the traditional song "Boston Burglar" but I only know the Leslie Fish version.

BANNED FROM BEAUMONDE

Our crew were in high spirits from a mostly painless job

And Jayne was extra chipper thanks to post from Mrs Cobb.

They each set out to celebrate in their individual styles

And left a trail of stories that were talked about for miles.

Chorus: And they're banned from Beaumonde, everyone.

Banned from Beaumonde, just for having a little fun.

They went to walk the world a spell, for just three nights or four,

But Beaumonde doesn't want them any more.

The Captain bumped into a girl he’d met two times before.

‘Bout both of those occasions he still felt a little sore.

He gave in when she made big eyes and told him all her woes,

That is until he woke to find she’d stolen all his clothes.

Chorus: And they're banned from Beaumonde, everyone.

Banned from Beaumonde, just for having a little fun.

They went to walk the world a spell, for just three nights or four,

But Beaumonde doesn't want them any more.

Inara found a client with the coin for her large fee.

She’d make enough in one night’s work to fund a spending spree.

She kept her poise when in their joys came a loud and angry yell.

With a sultry look she calmed his wife and serviced her as well.

Chorus: And they're banned from Beaumonde, everyone.

Banned from Beaumonde, just for having a little fun.

They went to walk the world a spell, for just three nights or four,

But Beaumonde doesn't want them any more.

When the Doctor finally asked her out, l'ill Kaylee squealed in glee.

But for Simon dates with women didn't run so easily.

It wasn't long before once more he'd put his foot right in.

She dumped him for a fella with a much bigger engine.

Chorus: And they're banned from Beaumonde, everyone.

Banned from Beaumonde, just for having a little fun.

They went to walk the world a spell, for just three nights or four,

But Beaumonde doesn't want them any more.

Wash wanted to present his wife with a k