You don't have to be off your head to watch the third instalment of fun and games with amiable stoner pair Harold and Kumar, but it would probably help.
It's been six years since their last misadventure, in Guantanamo Bay, and the friends have grown apart: Harold (John Cho) is now a pinstriped moneyman settled with a wife in the 'burbs, while Kumar (Kal Penn) still lolls in a den of smog and dope. The frantic quest for a jumbo-sized Christmas tree brings them together for a loopy night that starts with a car crash, passes through a Claymation dream and a Broadway dance routine, to end with an accidental shooting of Santa himself. The imaginative use of 3D projects all sorts – eggs, syrup, hats, smoke, a large crumb of cocaine – before our startled gaze, though even that isn't as risky as the running gag of a baby blitzed on pot and ecstasy.
Harold and Kumar remain the natural heirs of Cheech and Chong, though my favourite here is Harold's substitute bf Todd, played by the superb Tom Lennon as the squarest of squares. Horrified at the sight of partygoers nose-first in cocaine, he cries, "Have you kids never seen VH1's documentary Behind the Music?" Not this generation's White Christmas, but unrivalled for stupid fun.