My purpose in writing this is twofold.
First (chronologically: I thought of this earlier than the other), I want to discuss some of the pragmatic points in how I got myself to do it.
The most important thing is that I didn't try to force the decision through with willpower. Instead, I slipped it through with doublethink. I knew perfectly well - and have known for months - that giving money to SIAI was the right thing to do. But I didn't do it. I spent money on things like Minecraft instead.
But somehow I found myself at the donation page, and I didn't think about it. Or, rather, I didn't let myself think about the fact that I was thinking about it. I made a series of expected-value guesstimates aimed at working around my own cognitive limitations.
I chose monthly donation over one-time because $20 monthly sounds like about the same amount of money as $20; past experience with recurring donations suggests that I tend to leave automatic recurring donations in place for about a year or two, so that probably gained me about a factor of 20. Similarly, I chose $20 as the largest amount that wouldn't put me in serious risk of chickening out and not donating anything.
In order to pull this off, I had to avoid thinking certain true thoughts. Numbers like "$240 per year" only drifted through my consciousness just long enough to make the expected-value judgment, and were then discarded quickly so as to avoid setting off my rotten-meat hypervisor.
This was not the first time I decided that I should give money to SIAI. It was the first time I actually did give them money. (Except for that one time with the $1 charity-a-day thing, which actually might have helped with dissolving psychological barriers to the general idea.)
I think this is important.
The second fold of my purpose is to reinforce the behavior using the glowy feeling that comes from having other people know what an awesome person I am.1 Anyone else who's done anything worthwhile should feel free to post in this thread too.
1. It's true. Statistically speaking, I probably saved like a jillion people's lives per dollar. And more-than-doubled quality of life for a zillion more. Let me also note that you can get in on this action.
I know that sounds advertisementy, but... well, that's kind of the point. Practice Dark Arts on yourself for fun and profit.