  From 1995 to 1999, daily monitoring of the radio emission from the Crab
pulsar at the Green Bank and Jodrell Bank observatories revealed a series of
six sudden rotational spinups or glitches, doubling the number of glitches
observed for this pulsar since 1969. With these observations, the range of time
intervals between significant Crab glitches has widened considerably,
indicating that the occurrence of Crab glitches may be more random than
previously thought. The new glitch amplitudes ($\Delta\nu/\nu$) span an order
of magnitude from 2e-9 to 3e-8. Except in one case, which we suggest may
represent an ``aftershock'' event, the frequency jumps display an exponential
recovery with a timescale of $\sim$3 days for the smaller glitches and $\sim$10
days for the largest (1996) glitch. In the largest event, a portion of the
spinup was resolved in time, as was previously reported for the 1989 glitch. A
pronounced change in frequency derivative also occurs after each glitch and is
correlated with the size of the initial frequency jump, although for some of
the smaller glitches this appears to be a temporary effect. We discuss the
properties of the ensemble of observed Crab glitches and compare them with the
properties of Vela glitches, highlighting those differences which must be
explained by evolutionary models.
