These links are so popular, they appear on multiple news sites.
Follow the latest #1 links on Twitter.
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1[Digg, Mixx, del.icio.us]
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2[Digg, Mixx, del.icio.us]
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3[Mixx, Reddit, del.icio.us]
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4[Digg, del.icio.us]
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5[Reddit, del.icio.us]
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6[Reddit, del.icio.us]
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7[Digg, Reddit]
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8[Reddit, del.icio.us]
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9[Digg, Mixx]
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10[Digg, del.icio.us]
![Human Biological Clock [PIC]](http://upload.wikimedia.org/wikipedia/commons/5/5f/Biological_clock_human.PNG){kind=link}