That math looks like you are calculating the expected value of a raffle ticket randomly awarded to one donor with a value of 2000$.
But instead, the 2000$ is awarded to the charity that received the most donations in one hour. So we just have to donate more times than the second most-donated-to charity.
Oh, I must have misread it. I thought it was essentially a raffle.
I mixed it up with this part:
$150 added to a random donation each hour, every hour for 24 hours.
As you may know, on May 6, there will be a large one-day price-matching fundraiser for Bay Area Charities.
The relevant details are right here at MIRI's official website.
And this is the webpage to visit to donate.
For those of you who didn't read the two links above, here's the important information.