Pinkie Pie has taken over the Reddit banner as part of the Combined Community Charity Challenge that ran a few weeks ago. Have fun watching your entire day disappear by "just one more link" syndrome while basking in glorious Pinka. I already blew my morning as you can see above.
Thanks to Markster, Hackalot, and everyone else for the heads up too! I honestly didn't even notice until the submit box started exploding. I guess I just assume I'm going to see pony at some corner of my visual spectrum at all times.
Update: And go save those animals European guys!