Comet ISON has undergone a new spate of activity as it draws ever closer to the Sun, including wing-like features that typically coincide with some fragmentation of the nucleus. Furthermore, the TRAnsiting Planets and Planetesimals Small Telescope (TRAPPIST) team in Chile has found that ISON's gas production rates, which had decreased over the past five days, have increased abruplty by about a factor of six.
Check out the following links on the comet's activity:
Blogger Astro Bob has TRAPPIST astronomer Emmanuel Jehin's take on the comet's activity.
SpaceRef looks at the wing-like features with astronomer Hermann Boehnhardt of the Max Planck Institutre for Solar System Research.