Saturation curves (link to photoshop action)
This will be useful for punching up saturation without blowing things out--similar to pulling up the curve in an imaginary saturation channel. I'm sure people here will come up with more creative uses for it!
Is this what the vibrance slider in ACR or lightroom does?
|Christine by JP Zanotti|
from Car wreck
|Fangorn Forest by cand1d|
|Yosemite Falls with Moonbow by Jonathan Shapiro|
from Best Landscape of the Week 4