The Big Bang Theory

It’s Sheldon’s birthday and we learn why the occasion fills him with dread: he was bullied as a child and Batman never turned up to his party, as was once promised.

Under gentle pressure from his girlfriend Amy, Sheldon concedes to “cake, presents and a shower of admiration and love”. And the boys plan to right a few wrongs by inviting 60s TV Caped Crusader Adam West to the festivities. Cue some nicely nerdy “best Batman” banter.

From the off, The Celebration Experimentation is one enormous smile. All the gags work, there are a few surprise cameos (the guest of honour is very guessable to longtime fans) and plenty of pretty speeches – plus one of those thrilling little Penny-and-Sheldon moments the writers have such fun with. The story is not only a tribute to its lead character but to the show itself, now 200 episodes to the good. Fittingly, it’s celebratory, snappy and sweet.