Ever since 1985 I have been able to calculate what day of the week a given date is. My teachers in high school used to thumb through the calendar and pick a random day and ask me and I would always get it right.
So for years I would tell people what day they were born if they told me their birthday. Well fast forward to 2010 when suddenly everyone had smart phones. Starting around then, any time I told a (99% of the time female) person what day they were born they would then look it up on their phone and say "How did you know that??" So then they would almost always say "Tell me what day my boyfriend/husband/ex was born" and that was when I noticed that (the best) couples seem to normally be (often precisely) born 3 months apart. So then I realized my own relationships were always 3 months apart and I came up with a theory and every since relationship I've ever had falls into the pattern.
So now when a couple tells me their birthday I'll say things like "You guys started dating in September" -
"How did you know??" and you broke up last January but got back together in March" -
"Oh my God he is right..."
Then I happened to have a job interview with an Astrologist and he validated everything I said, and our charts looked strikingly similar! I had reinvented Astrology in a simpler form, just by memorizing dates. To me, my rediscovering it validates Astrology and vice versa.
I wrote an app for it this year, mainly to teach myself WebGL.
You can just put your birthday and her birthday in and see your best and worst days of the year. It's been remarkably accurate predicting my current relationship, in fact I predicted the exact day I would fall for her and the day she (will) fall for me (it happens on seasonal boundaries).
https://s3-us-west-2.amazonaws.com/juxtaposeweb/JuxtaposeA/Juxtapose.html