MB Moon Phase is a program that lets you calculate a moon's phase on a particular date, but that's its lone feature. According to the publisher's description, the program is free, but further inspection revealed a trial of 30 days and a donation once the trial expires.
When first installed, we were greeted with a ridiculously cluttered window full of donation requests. We had to root through the clutter to find the button that would let us continue with the program. From there, we were greeted with yet another cluttered interface. We entered a specific date and year, and clicked the Calculate Moon Phase button. The window then shrank and moved itself to the far right corner of our desktop. The phase of the moon according to the date we entered appeared in the tiny window, along with the current date and time.
If the phases of the moon are your thing, you might find this program worth the cost. However, we aren't too fond of programs that appear free, but in reality, aren't.