This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 License.
When you’re giving a presentation sometimes you want the audience to pay attention to you instead of your slides. In these cases remember these two keys: ‘b’ & ‘w’. The b key turns the screen black, while the w key turns the screen white. To return to the slides, just tap the relevant key again. (I think this works in Keynote too. Please feel free to confirm/deny in the comments.)