The emission of extra-galactic sources which have relativistic
outflows directed towards, generally known as Blazars, is dominated by
radiation from the jet. For a full(er) understanding of the mechanisms
behind the incredible amount of high-energy radiation produced by
these objects, simultaneous multi-waveband monitoring is a must. The
launch of the RXTE satellite signalled a new era in X-ray monitoring,
and the highlights from a major RXTE and optical/IR observing program of
two blazars will be presented. The physical implications for blazar
emission models will be investigated, and some thought given to the
future.