I don't know much about the Mayan calendar (beyond that some fuss has been made over it possibly running out in the not-so-distant future, as if this might have some dire implications), but I can help you with the other things. <img src="/images/icons/wink.gif" /><br /><br />The Sun has an eleven-year cycle (approximately). It may seem constant to us, but in fact it is slightly variable. It is most active during a period called Solar Maximum, when there are many sunspots and solar flares are much more common. The least active period is Solar Minimum, and we're about at that now. It's not totally predictable, though. The biggest solar flare on record occured quite recently, during what should've been a solar mininum. And there was a very long period of low solar activity called the Maunder Minimum (somewhat disputed; it's known from records that predate accurate reporting of sunspot activity), which may have contributed to the Little Ice Age, a cold period that caused famine across the medieval world, especially in Europe, robbed of its Gulf Stream warmth.<br /><br />2014 should be a time of more activity on the Sun -- solar maximum.<br /><br />There will be a total solar eclipse visible from the United States in 2017.<br /><br />Venus will be participating in an interesting event soon, though. In 2012, it will transit the face of the Sun. This is a very rare event; the last one occured in 2004, but the one before that predated living memory. Venus transits usually come in pairs less than a decade apart, but there is more than a century between those pairs. The next transit will occur in 2117, so it's a big deal. <br /><br />(Edited to correct boneheaded goof.) <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>