  Using two identical telescopes at widely separated longitudes, the ROTSE-III
network observed decaying emission from the remarkably bright afterglow of GRB
030329. In this report we present observations covering 56% of the period from
1.5-47 hours after the burst. We find that the light curve is piecewise
consistent with a powerlaw decay. When the ROTSE-III data are combined with
data reported by other groups, there is evidence for five breaks within the
first 20 hours after the burst. Between two of those breaks, observations from
15.9-17.1 h after the burst at 1-s time resolution with McDonald Observatory's
2.1-m telescope reveal no evidence for fluctuations or deviations from a simple
power law. Multiple breaks may indicate complex structure in the jet. There are
also two unambiguous episodes at 23 and 45 hours after the burst where the
intensity becomes consistent with a constant for several hours, perhaps
indicating multiple injections of energy into the GRB/afterglow system.
