Advent of Code 2017 - SmartyStreets Sponsor Text

I just learned about the Advent of Code -- an event with a new short, fun programming puzzle published in each of the 24 days leading up to Christmas.

I noticed that primary event sponsor SmartyStreets has some cryptic text as their sponsor comment:

U2VuZGluZyBDaH Jpc3RtYXMgY2Fy ZHMgdG8gYmFkIG FkZHJlc3Nlcz8K

I won't spoil what it says here, but the only hint you should need to decode the text is that it is base64 encoded. (Also, automatic base64 decoder websites are readily available!)

Also, I'm publishing my C# Advent of Code 2017 solutions on GitHub. I'm generally aiming to optimize them for readability, rather than for minimum lines of code or fastest possible execution speed -- which is what I generally do as well when writing actual production code.  That being said, I have been pretty blown away by the impressive brevity of the solutions of some of the event leaderboard's top members!