  We use time-resolved dynamic light scattering to investigate the slow
dynamics of a colloidal gel. The final decay of the average intensity
autocorrelation function is well described by $g\_2(q,\tau)-1 \sim
\exp[-(\tau/\tau\_\mathrm{f})^p]$, with $\tau\_\mathrm{f} \sim q^{-1}$ and $p$
decreasing from 1.5 to 1 with increasing $q$. We show that the dynamics is not
due to a continuous ballistic process, as proposed in previous works, but
rather to rare, intermittent rearrangements. We quantify the dynamical
fluctuations resulting from intermittency by means of the variance
$\chi(\tau,q)$ of the instantaneous autocorrelation function, the analogous of
the dynamical susceptibility $\chi\_4$ studied in glass formers. The amplitude
of $\chi$ is found to grow linearly with $q$. We propose a simple --yet
general-- model of intermittent dynamics that accounts for the $q$ dependence
of both the average correlation functions and $\chi$.
