ICA, The Mall, London SW1 (0171-930 3647), today from noon to 1am
On 29 April 1967, The Fourteen Hour Technicolour Dream Free Speech Benefit took place at Alexandra Palace to raise funds for the underground newspaper International Times, which had been closed down by the government. To celebrate the 30th anniversary of the event, the ICA is hosting what promises to be a day (and night) of hippie heaven, featuring 13 hours of speakers, performances, films, DJs and live bands spanning 1960s psychedelic rock to Detroit techno, from New Delhi ragas to trip-hop and freaked out acid garage. Highlights include legendary filmmaker Peter Whitehead, Jimi Hendrix biographer Charles Shaar Murray and Pete Brown from Cream. There will be fruit, water, milk and honey for sustenance as psychedelia takes on a nineties spin. Cool.