Super awesome app I found in the LDR tags of Tumblr called Dreamdays. It’s a cute countdown app for iOS only. (Sorry Android folks, trust me, I looked because I have a Android-based phone.)
There is a free ad-supported version and a $1.99 version that removes ads (and probably adds some other features but I went for the free version because I am a cheapo.)
Only downside is that you have to open the app to see where your countdowns are at, they don’t show up in Notification Center. I’m guessing it will when the day finally comes.