Bear Grylls lifts Stephen Fry out of his comfort zone

As we deck the halls with boughs of holly and prepare for the imminent arrival of the jolly red fat man, British survivalist Bear Grylls spends a high-octane 48 hours with lanky but loveable polymath Stephen Fry in Bear's Wild Weekend, which airs tonight on the Discovery Channel at 8pm. Known for his brains rather than his braun, man-about-town Fry is forced to face some of his deepest fears when he joins the extreme outdoorsman in the Italian Dolomites. Pushed to his physical and mental limits by Grylls, the oafish Fry provides ample comic relief as he swears his way down the mountainside.

In between traversing icy waterfalls and feasting on deer's heart, the British national treasure shares some poignant moments with Grylls; the pair explore their conflicting beliefs on politics and religion, and discuss profound moments from their past.

Bear's Wild Weekend works well because the chief scout has eased back on the testosterone. And with Fry taken way out of his comfort zone, we get to witness a vulnerable side that the Cambridge-educated comedian rarely reveals, further endearing us to the thoroughly splendid chap he so obviously is.

Fellow battle-the-elements reality show Tethered (Discovery Channel, December 30 at 8pm) sees two strangers with vastly different backgrounds and characters bound together by a six-foot cable and dumped in the wilderness with one aim: to escape. Armed with a limited survival kit, they must work together to travel across treacherous jungle terrain and reach the rescue point within 10 days. Can they survive the wild and, more importantly, resist killing each other?

This week, stranded on a desolate archipelago off Panama's Pacific coast, are my-way-or-the-highway ex-soldier Keith and a tree-hugging yogi called Willow. After an unsuccessful first day, in which they managed to get no food, water or sleep, both are noticeably irritable. Making matters worse, every time one of them bitches to camera about the other, the object of their scorn is no more than six feet away.

Of course, this makes for ideal television and, as they struggle across swamps and shark-infested waters, Keith becomes more concerned by Willow's use of eyeliner than any snake or spider they might encounter. It's not difficult to predict the final outcome and the inevitable bonding of "enemies", but this celebration of the human spirit is particularity apt for this time of goodwill to all mankind.

Possibly the last person I'd want to be tethered to for a week is jester pest David Blaine. For more than a decade Blaine has been irritating the world with his high-profile feats of endurance in an apparent quest to prove he's some kind of mystical shaman. Whether he's being drowned, frozen or buried alive, his big stunt shenanigans have always left me a little confounded as to why he bothers. Admittedly, I enjoyed the furore surrounding the 44 days Blaine spent fasting, suspended in a glass box above London's River Thames. But that enjoyment was gleaned from onlookers' attempts to scupper the endeavour by flying cheeseburgers up to him using remote-control helicopters.