Here's another trick to add to the bunch. It uses a duplicate of a luminosity mask. For this procedure I'll use a Lights mask on a curves layer, but one can use any of the luminosity masks on either a curves or levels layer.

1. Create the first Lights mask.
2. Duplicate this mask.
3. Set the blending mode of the mask created in step 1 to Screen
4. Set the blending mode of the duplicate mask created in step 2 to Multiply
5. Adjust the curve in either, or both, layers to suit.

Basically, the Triple Play (TP) action does the same thing, but this procedure works well if you don't need all the layers and the halo separator layer of the TP.

Since Michael mentioned the TP, I'll echo his sentiment about it--it is really nice, and has really helped in difficult situations.

--P