I use altcoinherald.com. They have just about everything on their calendar. If they miss a ninja launch they'll backfill.
I'm sure there are WAY better resources out there...but this is the one I use: http://www.cryptolaunch.net/
Hope that helps!

That site is very good, but even that wouldn't help in some special cases where the launch is extremely obscure. For example, Bytecoin (BCN) which was launched in the deep web.