According to The Jam’s ‘That’s Entertainment’, watching the telly and thinking about your holidays is entertainment, as is a hot summer’s day and sticky black tarmac. Of course, Paul Weller’s ironic take on working class Britain was not what he truly believed entertainment to be, but its mundanity and seeming randomness are quite appropriate when it comes to working out exactly what our children find entertaining.

We’ve all been there on Christmas Day, haven’t we, when our bubble of parental anticipation at little Johnny opening his big present is rudely punctured when he opens it up, goes “meh” and spends the entire day playing with the throwaway £1.99 stocking filler you bought at Poundland instead, despite your best efforts to cajole him into playing with the toy that you were convinced – or which he convinced you four weeks before – was going to be the Toy To End All Toys®.

I’d love to know what goes on inside our three children’s minds that determines whether a toy or activity is a ‘hit’ or a ‘miss’. With Kara, it’s still pretty easy – if she can pick it up, insert it into her mouth and chew on it, it’s a winner. But with Isaac (five) and Toby (three), I would have more luck forecasting next week’s lottery numbers than predicting what they will (or won’t) find entertaining.

Actually, that’s not strictly true. If it has a touch-screen and an Apple logo on the back, it’s a sure-fire winner. But beyond that it gets a little trickier.

Yesterday, for instance, we were at a hotel for a 40th birthday party for one of Heather’s friends. What excited Isaac the most? The prospect of haring around a large open space with his friends? Party food? Helium balloons? Well, the balloons were a hit – although the last time we bought in balloons for one of the boys’ parties, both Isaac and Toby were utterly nonplussed by them (they’re so fickle!). But no, the one thing Isaac wanted to do above all else – the one thing he remembered about the hotel and which got him squealing with anticipation as we were driving down – was the revolving door at the entrance. Yes, a revolving door.

At one point, after he had just spent the previous 15 minutes with his mates running around the room trailing balloons after them, he stopped, came up to me and asked me if I could accompany him to said door. And so that’s what we did. We traipsed out to the lobby where – much to the amusement of the girl on reception – he proceeded to walk round and round in the doorway, counting out the number of revolutions he completed as he did so. (I’d told him he could do five. He asked for ten. As always, he won the negotiation.) I don’t think I saw him any happier all day, and I’m convinced that if I’d left him to his own devices ten revolutions would have become 20, 50 and then 100.

I think I’m going to have to compile a list of what he finds entertaining at different points in his life, as it changes so fast. Much of it is the kind of stuff most boys of his age like. Rollercoasters and water slides. Riding his bike as if he’s the next Mark Cavendish. Scooby Doo (the pre-Scrappy Doo version, obviously) and Top Gear. Pop music, as long as it’s no older than 2008. (He has a sixth sense that allows him to immediately identify and reject anything older than that.) But it’s all the other things – the stuff that is a bit different, a bit quirky and sometimes just downright weird – that really tell the story of who he has been, who he is and who he is becoming as an individual. His brief Angelina Ballerina phase and his long-standing love of all things pink. His progression in musical tastes, from Lily Allen via Rihanna to Nicki Minaj. His borderline obsession with train-based iPad strategy games and Trivial Pursuit.

It’s all part of what makes him Isaac, and that unpredictability of what he finds entertaining and what the next big thing will be for him is a huge part of the joy of fatherhood for me. Although if he starts singing that Taylor Swift song again, there’s going to be trouble …

Finally, just because it’s a brilliant song, here’s The Jam (although, obviously, because it’s ‘old’ music Isaac won’t listen to it):