The PowerPoint Color Bug on Macs
There's a incredibly odd bug in PowerPoint 2011 on the Mac that causes colors to render differently when they are applied to shapes and text. Even when the exact values are applied to a PowerPoint shape and to a block of text, they will appear slightly different on the screen.
There's still no official fix from Microsoft on this yet, but Jan Schultink at Idea Transplant has been working on the problem and has come up with a solution. Read about it here.
PPTFaq also has some info on this issue here.