Formula 1 testing gets underway at the end of this week in Bahrain, as the 2021 season takes another step closer to lights out at the end of March.Naturally, there's an air of excitement at this part of the year as we wait and see who the challengers to Mercedes are going to be and, indeed, if there are any surprise packages.It's also the time of the year the drivers have been looking forward to after a few months off and, during that time, they'll have been bidding to keep themselves sharp ready for another long campaign.What sort of weird and wonderful stuff have they been up to since the chequered flag in Abu Dhabi last year, though? We take a look now...Lewis HamiltonWe kick off with the reigning champion. Lewis Hamilton is looking to make it eight titles this season and is well known for keeping himself active during the off-period. We've seen him working on his music, surfing and, perhaps most intensely, cross-country skiing as he aims to break more records in 2021.

Valtteri Bottas 

Trying to keep up with him across the garage is team-mate Valtteri Bottas and, not to be outdone, he's been getting up to all sorts too. The Finn has spent time in Lapland on snowmobiles and also took part in an Arctic rally whilst also cycling in slightly sunnier climes.

Kimi Raikonnen

Compatriot Kimi Raikkonen has also been enjoying some snow-based frolics between seasons but at a slightly slower pace.

His Instagram is good value for a laugh and his snowman building caught the attention on one of his stories earlier this year:

Pierre Gasly and Charles Leclerc

Not everyone's been in the cold in recent months, however, with the likes of Pierre Gasly and Charles Leclerc opting for sand over snow.

Antonio Giovinazzi and Daniel Ricciardo

The thirst to try different sports didn't stop there, meanwhile, with Antonio Giovinazzi taking to the golf course whilst Daniel Ricciardo impressed with his basketball skills.

Indeed, the Australian has been busy since the last race of 2020 with him also launching a new wine collection ahead of what he hopes will be a vintage season in his first at McLaren.

Whilst he's on the drinks, Nicholas Latifi could be able to sort the food with him demonstrating an evident love for pancakes back on Shrove Tuesday.

Sebastian Vettel 

And an off-season round-up this year wouldn't be complete without a look at Sebastian Vettel's new hair.

The beginning of a transplant? Or just a new aerodynamic style? Time will tell this season and he'll hope that's only a minor sub-plot as he bids for a return to success with Aston Martin.

It's not all been fun and games, though, with the drivers also regularly showing their training work ahead of a 23-race season - the longest in F1 history.

Fernando Alonso and George Russell 

Fernando Alonso has been working his neck ahead of a long-awaited return and, indeed, after jaw surgery following a cycling crash.

George Russell has been doing similar, meanwhile, with a matrix-level exercise by the looks of things.

And, finally, Mick Schumacher has been studying hard in England ahead of the new season as he prepares for his F1 debut.

That, or he's got himself engrossed in Football Manager in recent months.

The season is almost upon us, then, and we'll soon get an idea of who has got their preparations right with the first race in Bahrain on March 28th.