Add event listing design

Here's a quick shot at an event listing design. Should be pretty flexible and handle whatever content you've got.

Screenshots:

![desktop](https://cloud.githubusercontent.com/assets/808159/3354114/c98332b2-fa98-11e3-9836-9dfed78838f1.png)

![small-tablet](https://cloud.githubusercontent.com/assets/808159/3354115/cbfc3516-fa98-11e3-84dc-aaf9546818fd.png)

![mobile](https://cloud.githubusercontent.com/assets/808159/3354119/ce837dc6-fa98-11e3-8eb2-7ef289ec707b.png)

/cc @crabasa