What does your calendar say about you?

From the flying lovelies of Ryanair, to the pick of Her Majesty's nicks, and the nation's swankiest sheds, there's one for everyone, says Michael Bywater

As a schoolboy temporary postman each Christmas, it was the calendars that did for me. My walk was through a poor district of town, where it was the thought that counted. Each morning my sack was filled with such thoughts, in the form of calendars. Thousands of them.

Aunties to nephews, Nan to grandkids, Sis to Bro. There they were in their stiff brown envelopes printed "CALENDARS DO NOT BEND". Oh yes they bloody do. And they had to, because the calendar-receiving sort lived in little houses with narrow, ground-level letterboxes. Fold, stoop, push, up. Fold, stoop, push, up. Fold, stoop, bark, bite, ow, up. And all so that the recipient, who probably didn't know what day it was, could find out what day it was once the year turned. Lovable cats, rural scenes (thatch, spire, pub), wide-eyed babies, improbable flowers. How we posties hated them.

But times move on. Calendars – once the treasured product of clerics and sages hunched in their scriptoria, calculating the ephemerides of tides and eclipses, floods and transits – have diversified into a parade of sheer joyful lunacy. The information is irrelevant, and available in a thousand other forms. The granularity of our lives is no longer in the month or the day or even the hour. Nowadays, the main benefit of the calendar is not that it tells you the date, but that it lasts all year. Car people cottoned on to this ages ago, with their naked lady calendars advertising tools and tyres and other car stuff. They hung on walls until the following New Year's Day, though sometimes they got stuck or fast-forwarded to a particularly appealing lady, gradually obscured by oily thumb-prints.

And, like all good ideas, it's gone simultaneously global and specialist. There are almost certainly closed, secretive networks of imerologiophiles or ephemerasts or whatever they call themselves, having tremendous fun with swaps and meetings and secret handshakes.

But what of the non-enthusiast, non-ironic calendar-buyers? What is the state of mind of someone who buys the Luxury Shed Calendar, or the Ferries of the Irish Sea 2009? They can't all be Clerkenwell loft-dwelling ironists, which suggests that there is a significant number of people hunched by the boiler (the calendar always hangs over the boiler) waiting for the end of the month so that they can see, and gasp over, next month's Luxury Shed ("I think you'll find that's Cuprinol, not creosote, actually") or flip, gasping, to the next Irish Sea ferry ("That's the Stena Lynx III; recognise it anywhere"), as photographed by the "well-known Irish Sea ship photographer Gordon Hislip whose work appears in European Ferry Scene".

Are there men hunched in the muddy shires taking bets on April's entry in the Tractors 2009 Wall Calendar ("It'll be a Massey Ferguson MF-35 in blue, you mark my words, young Ezra")? Are numismatists eagerly awaiting New Year's Eve to pin up their Royal Mint Deluxe Wall Calendar? Yes, and yes: you bet.

But even more worrying is the assumptions of people who give these things as a gift. You may feel a fool if you have to be nice about the Original Pink Flamingo 2009 calendar, but you should really be wondering why the hell Uncle Marjorie gave you the thing in the first place. And what does it say about you if someone gives you the West Yorkshire Catholic Church Calendar in which 12 priests swap cassocks for everyday clobber that depicts their hobbies (please, please let there be one in a sou'wester and a whalebone leg) in an effort to attract more men to joining the Church. (As opposed to the one I got in Rome, showing priests in the, my dear, most lovely Gamarelli soutane, and so chiselled, which also would attract men to the priesthood, no question about that, darling.) What does it mean if your friends think you're the sort of person who'd like looking at a fresh picture of guinea-pigs playing games each month, or the kind of wacky sod who really would tear off his Paper Airplane Fold-a-Day 2009 and actually fold an actual aeroplane?

It's a mystery. As is the Ryanair Cabin Crew Charity Calendar showing a gaggle of in-flight popsies in swimwear posing on an aeroplane, yet looking every bit as cross as they do in their official uniforms.

But I can unreservedly recommend two of this year's crop to the intelligent realist. If you want to be reminded each recessionary month of Britain's last surviving growth industry, then Her Majesty's Prisons of England 2009 calendar is just the thing. And if even that doesn't match your mood, go to calendar.despair.com and grab yourself a 2009 Demotivator Calendar of Despair. Happy New Year; but don't count on it.