Game of Thrones, Sky Atlantic, Sunday The Undateables, Channel 4, Tuesday Marrying Prince Harry, Channel 4, Friday

The return of a cult fantasy show tempts even a sceptical viewer to mug up on myths and maps

Fantasy is not a genre for the lazy. Nor, arguably, for those with better things to do than memorise labyrin-thine imaginary family trees and maps of fictional countries. In the run-up to the start of season two of Game of Thrones – HBO's award-winning adaptation of George R R Martin's epic sword-and-sorcery novels – there was certainly plenty of homework to do. The GCSE-worthy crib notes, recapping the first series for newbies, were for me a reminder of precisely why I hadn't tuned in last time.

Despite the buzz, the recommendations from friends (who don't, as far as I know, spend their weekends dressed as knights in a wood in Norfolk) and the critical acclaim, I couldn't shake the feeling that the world we've got is quite interesting enough to preclude the need to invent others in pedantically minute detail. No doubt the best fantasy uses its alien scenarios to reflect all the more powerfully on what's familiar – and Game has been lauded for just that – but when it comes to dungeons-and-dragons theatrics, it's easy to lose the wood among the trees.

The first instalment had a way to go, then, to persuade me otherwise and though the Sopranos-meets-Conan-meets-The West Wing-meets-Rome comparisons still seem on the feverish side of fandom, the show is a more enjoyable affair than I'd expected. The first episode was principally a scene-setter, re-introducing us to the rival families fighting (mainly amongst themselves) for the throne of the kingdom of Westeros, so was unlikely to contain insights into the nature of power and conflict that one might expect to emerge over time.

The plot is heavy with spoiler-potential – and since many are still watching the first series on DVD, it would be mischievous to recapitulate the story so far. But the newcomer can more or less keep up with distinguishing Lannisters from Starks and friends from enemies or frenemies. What hooked me, if anything, were the spectacular visuals and all-round filmic quality that make this a classy watch. As far as the content goes there's a pleasingly trashy streak, even if the sex and violence quotient was, I'm told, uncharacteristically low in the first episode.

There is also a humour not normally associated with the genre, and the script is at its best when its tongue is firmly in its cheek, giving all the best lines to antihero Tyrion Lannister, played by Peter Dinklage, who needs little help in hogging the screen. "You love your child; it's your one redeeming quality" he archly tells his beautiful, morally bankrupt sister. "That and your cheekbones."

If I was unsure about Game of Thrones, I felt positively nervous about The Undateables, the first in a series of documentaries about a group of young people with various disabilities joining a dating agency. Not only did it sound like a nasty little piece of voyeurism (nice title, folks), it also threatened a depressing portrait of the brutal nature of modern courtship.

In the event, it came closer to the latter, though not because the participants faced hard luck in their search for love. On the contrary, Richard, an Asperger's sufferer, and Penny, 3ft 3in, had to gently decline a second date, while Luke, who has Tourette's syndrome, looked to have struck it lucky with his match.

A revealing – and dismaying – moment came when 6ft 1in Richard gave his height to the lady compiling his dating agency profile. "Height is very important," she divulged. "So you're what we would call a good commodity." In the contemporary world of online dating and matchmaking, if you can't sell yourself via a photo or a pithy one-liner or your vital statistics, you may well feel you're in the bargain bin.

All that may await the girls who featured in Marrying Prince Harry – that is, if they fail in their aims to wed the prince. If you tuned in expecting loopy obsessives, you might have been disappointed by this portrait of anodyne teen crushes. Joy, a charming, articulate 16-year-old from Chingford, explained that she was drawn to the idea of marrying a man nothing like her father, who had walked out when she was nine.

Most interesting was the importance of Twitter for the hobbyist stalker; the closest we got to HRH was outside a charity do thanks to a tip-off tweet. "Facebook is for friends," explained one of the girls, "and Twitter is for stalking celebrities."