Billed as the potential "comet of the century", Comet ISON has gone through an outburst in the past few days, a brightening that has taken it to Mag +5.5, so that it's now visible through the naked eye from a dark location.
With the proviso that the brightnesses of these comets are notoriously difficult to predict, it's hoped it's gonna get brighter and brighter over the next couple of weeks, with some optimistic predictions that it'll get as bright as a Full Moon. We'll have to wait and see.
Look for it over towards the east to south-east in the hour or two before dawn.
http://www.cometison2013.co.uk