How can I build the white/green Container (shaped Polygons) with CSS / CSS3 ?

How can I build the white/green Container (shaped Polygons) with CSS / CSS3 ?

You could use a basic SVG path
http://codepen.io/anon/pen/XbaKLp
<svg width="300px" height="100px" version="1.1" xmlns="http://www.w3.org/2000/svg">
<path d="M5 5 L170 3 L295 15 L280 95 L130 80 L110 95 L20 85" stroke="transparent" fill="#8eab32"></path>
</svg>
Mx y represents the first coordinates;Lx y represents a straight line from previous coordinates to (x, y).(you can find further information about path on MDN)
Result

Then you may add text or markup inside the SVG using the <foreignObject>...</foreignObject> element, e.g. suppose we need to insert a link
<svg width="300px" height="100px" version="1.1" xmlns="http://www.w3.org/2000/svg">
<path d="..."></path>
<foreignObject width="100%" height="100%">
<a href="#">noch 356 tage</a>
</foreignObject>
</svg>
along with some basic CSS
svg {
line-height: 100px;
text-align: center;
}
svg a {
color: #fff;
font: 36px "Indie Flower";
text-decoration: none;
}
the final result is http://codepen.io/anon/pen/QbMEeW

and you can even apply some CSS transformation to the SVG element itself, e.g.
svg {
transform: scale(.6) rotateZ(-2deg);
}
so it can look as in your example.
You could use a clip path for this: (although I have to admit, browser support isn't incredible):
body {
height: 100%;
background: #222;
}
div {
height: 100px;
width: 200px;
line-height: 100px;
text-align: center;
background: rgb(180, 255, 50);
-webkit-clip-path: polygon(0 5%, 60% 0, 100% 20%, 98% 100%, 50% 85%, 40% 100%, 5% 90%);
}
<div>This is clipped</div>
further reading:
you could also create such a shape using SVG:
html,
body {
background: gray;
}
<svg version="1.0" xmlns="http://www.w3.org/2000/svg" width="400px" height="200px" viewBox="0 0 100 100">
<g fill="green" stroke="black">
<path d="M 0 5, 60 0, 100 20, 98 100, 50 85, 40 100, 5 90z" />
</g>
</svg>
disclaimer
Please note I am still learning SVG myself, so it may require some tweaking of values.