Hi, I thought you may like this Mentalrobics exercise from Braingle.com:
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Distractions

Our attention is easily diverted by any number of distractions (a song on the radio, an overheard conversation, an itch, etc). The next time you need to concentrate on something, pay attention to what distracts you from your task. What types of things divert your attention? How does it feel to be distracted by something against your will?

If you become aware of which types of things can easily distract you, you can try to block them out when you need to concentrate. For example, you could turn off the radio if you are easily distracted by music.
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For more mind exercises: http://www.braingle.com/mind/