If you like to mess around with post-processing filters, onOne is giving away Perfect Effects 8 through Jan. 28. You can d/l standalone app as well as plugins for Lightroom, Aperture, PS, etc.
Usually sells for $99.
Had a quick look and I still prefer the Nik system but you can't beat free.
http://www.ononesoftware.com/landing/pe8offer/
P.S. this is fully licensed premium version, not demo.