Rosberg fastest, Hamilton 2nd, Hulkenberg 3rd
Vettel spins off at end of rain-interrupted session
Vettel gets gearbox grid penalty as Ferrari postpone running 'halo'
So, the two Mercedes are top of the charts for a change.
But the weather suggests we might have an unpredictable weekend, with tyre tactics important.
Join us again tomorrow morning at 09:30 BST for build-up to third practice and then qualifying.
In the mean time, read Andrew Benson's report on today's shenanigans.
Kimi Raikkonen on Sky Sports: "We didn't get too many laps done with the conditions. So it's a bit unknown."
What about the yellow kerbs?
"It doesn't matter what colour the kerbs are."
Well, yes, I guess that's true.
Another standout performance there is from Carlos Sainz - P6 for the Toro Rosso man. His team-mate Daniil Kvyat was half a second slower.
#bbcf1
Caroline Rosebery: I would choose François Cevert, I would love to know how his career would have progressed and Jenson Button.
José Carlos Costa: Dream team? Michael Schumacher and Lewis Hamilton, any battle of those two in a wet race would be epic.
Spencer Chainey: Ayton Senna and Gilles Villeneuve. No brainer pairing for me.
Lewis Hamilton has taken up a position on the grid to perform a practice start.
Guess which position he went for?
Pole.
Very optimistic, Lewis.
Just getting a look at Vettel's tyres from an aerial view - they're worse for wear.
Allan McNish
BBC Radio 5 live Formula 1 analyst
It's all going to be about the management of the ultra soft tyres. It's definitely the quickest tyre.
Nice work by Nico Hulkenberg and Force India, who take P3.
Vettel is in P4 and then Daniel Ricciardo in P5.
Image source, AP
So, Nico Rosberg looks set to top second practice, as he did in first practice.
He's gone 0.019 seconds quicker than Lewis Hamilton.
You'd barely get a sheet of paper between them.
Image source, Reuters
That means the yellow flag comes out and that will signify the end of any meaningful racing second practice.
Sebastian Vettel is off at Turn Two, sliding casually sideways through the gravel towards the tyre wall.
"I have no idea what happened. I lost control when hitting the brakes," he tells Ferrari on the radio.
Image source, Getty ImagesIt's a busy track for the final four minutes, as Felipe Massa sets a personal best for the afternoon in P11.
We're into the final five minutes. Lewis Hamilton's hopes of clocking a quick time are fading, as he runs wide and then finds a bit of traffic.
Image source, Getty ImagesNico Rosberg has just picked up a 1:08.516 on the super softs.
His Mercedes team are waiting for him in the pits though - they have some lovely purple-trimmed ultra soft tyres for the championship leader.
Image source, Getty ImagesEsteban Gutierrez gets right in Lewis Hamilton's way on Turn Five - the Haas driver receives the message to slow too late.
That means Hamilton has to lock up to avoid the Mexican.
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CJay: Dream team: Jochen Rindt and Alain Prost, lunacy at its best.
Jorge Lorenzo: For me it has to be Hamilton and Alonso... pretty much the two most electrifying drivers of this era!!!
Matthew Goff: Jack Brabham and Mark Webber, but I might be a tad biased!
Alonso, Magnussen, Palmer and Massa are the only men in the pits at the moment.
No sign of either Mercedes yet. They're primed and ready... wait. Here they come.
Nico Rosberg on the super softs.
Lewis Hamilton will follow on the ultra softs.
Claire Cottingham
BBC Radio 5 live pit-lane reporter