  PSR B0823+26, a 0.53-s radio pulsar, displays a host of emission phenomena
over timescales of seconds to (at least) hours, including nulling, subpulse
drifting, and mode-changing. Studying pulsars like PSR B0823+26 provides
further insight into the relationship between these various emission phenomena
and what they might teach us about pulsar magnetospheres. Here we report on the
LOFAR discovery that PSR B0823+26 has a weak and sporadically emitting 'quiet'
(Q) emission mode that is over 100 times weaker (on average) and has a nulling
fraction forty-times greater than that of the more regularly-emitting 'bright'
(B) mode. Previously, the pulsar has been undetected in the Q-mode, and was
assumed to be nulling continuously. PSR B0823+26 shows a further decrease in
average flux just before the transition into the B-mode, and perhaps truly
turns off completely at these times. Furthermore, simultaneous observations
taken with the LOFAR, Westerbork, Lovell, and Effelsberg telescopes between 110
MHz and 2.7 GHz demonstrate that the transition between the Q-mode and B-mode
occurs within one single rotation of the neutron star, and that it is
concurrent across the range of frequencies observed.
