Fr Ray Blake has started a petition to the Holy Father asking him to restore the Octave of Pentecost.
At Fr Mark's blog, Vultus Christi, you can read an interesting story of Pope Paul VI and the suppression of the Octave. See: In Praise of the Octave of Pentecost (click the "continue reading" link.)
Sign the petition here.
(If you don't live in the UK, just leave the "region" tag blank.)