It's not a rule, but a weird food thing. I eat in even numbers.

So when eating a handful of M&Ms, I go by color, and if there are an odd number of a color I'm on, I go with another color which is also odd next. I don't care if I actually eat an odd number of candies/chips/whatever. What I care is that I eat in even numbers so I know when I'm done if there were an even or odd number. I don't keep track over time or anything, so it's kind of bizarre.
The pews never miss a sermon but that doesn't get them one step closer to Heaven.

But at least the pews never attend yoga!