So right now On One software is giving away their Perfect Effects 8 plug in for Lightroom and Photoshop. The app can also be used as a standalone program if you like to edit things that way as well.
In the past I mostly only use the plug ins from Nik software and they are awesome but On One has some other cool features worth checking out, especially considering its free right now!
You can get it from their site here. http://www.ononesoftware.com/products/effects8free/
Here's a few images from a recent all day Prewedding shoot I did where I played around with some of the effects in Perfect Effects 8.