You can add 0,5% TCE(trichloroethanol) to the gel. Directly after running the gel you can visualize it under UV light (~30sec exposure). See this paper for more info: http://www.ncbi.nlm.nih.gov/pubmed/14769330
Most of Biorad's precast gels contain TCE already, the call it stain-free technology
If you are starting with a purified protein, or even with a crude extract, you can react it with a fluorescent dye that reacts with lysine residues (the buffer must not contain primary amines such as Tris in order for this to work). Then, after you run the gel you can see the proteins using a fluorescence imager.
Which color do you want? Yes, if you're insisting on a visible wavelength dye, you can just add Remazol dyes or dabsyl chloride dyes at alkline pH and then quench with a primary amine like lysine. Blue, red, green, orange, purple, blue (no polka dotted).