Most are too young to be even vaguely aware of Woodstock Music and Art Fair these days. But the impact of the three-day celebration of peace and music on a dairy farm in Bethel, New York back in 1969 marked the pinnacle of the hippie era and saw nearly half a million people descend on the 600-acre site. Acts included Janis Joplin, Joan Baez, The Who and Jimi Hendrix and the fest was an unprecedented event in music history.

Ang Lee's Taking Woodstock is the tale of Elliot Tiber (oddly renamed Teichberg in the movie), president of the Bethel Chamber of Commerce, who held the only permit for a music festival in the area (he planned to put on a chamber music show) and invited the event's organisers to the town when they were denied a permit in the nearby town of Wallkill. Based on his autobiography, we join him as a young man (Demetri Martin) struggling to maintain his parent's motel business and coming to terms with his sexuality.

When he reads that the permit for the Wallkill has been pulled, he pitches the idea of bringing the festival to Bethel to promoter Michael Lang (Jonathan Groff). Before long, plans are underway to run the show on Max Yasgur's farm, proving a much-needed investment of capital into Tiber's motel, which the organisers use to house themselves and their offices while the show comes together.

The film is really about Elliot's journey without moving. While struggling with his own identity and his responsibilities to his parents - a battleaxe mother (Imelda Staunton) and ailing father (Henry Goodman) - he welcomes an incredibly liberal collection of people to his town who teach him the value of personal identity. It's an incredibly powerful theme punctuated brilliantly by Liev Schreiber as a transvestite ex-marine, of whom Elliot asks if his father understands what he is. He replies, "Honey, I know who I am. That should make it easier for everyone else."

Maybe it's not surprising to see a film with powerful homosexual themes from Lee, who was nominated for a Best Picture Oscar for Brokeback Mountain, but he explores the subject with an impressively deft hand, making Elliot's journey remarkably genuine. The real Tiber was present for the Stonewall riots, which happened weeks before the film's timeline begins, but Lee and screenwriter James Schamus focus their adaptation on a young man whose sexuality isn't so assured before the film begins and allows the audience to take the film's journey with him.

It's not quite as successful in that respect as Almost Famous, another film about a young man's journey into the world of live music, as Patrick Fugit's character in that film is, perhaps, less affected by a history that isn't spelled out within the film. But Taking Woodstock is as much about Elliot's journey as it is about the foundations of the music festival. In the clash of big business and hippie ideals that gave birth to the show it's a film both funny and engaging. On the sidelines, Emile Hirsch as a Vietnam vet and Paul Dano as an Acid-dropping hippie provide drama and comedy respectively, while Dan Fogler is hilarious as the leader of an alternative theatre troop whose main artistic contribution to the world seems to be to dance around naked.

When the festival kicks off, Elliot is nowhere near the action - if nothing else, clearing rights to that material would have been mighty tricky - but Lee gives a comfortable sense of scale in cleverly chosen CG shots mixed, predominantly, with vast scenes involving extras.

It may not be on a par with Brokeback, nor as powerful as Lust, Caution, but Taking Woodstock is another triumph for Ang Lee, a director whose resume gets more and more diverse with every project he tackles.