I don't know you well enough to really answer this question. You probably need to talk with a college counselor who knows you better. But if you write personal essays on cubing, I'm sure we'd all like to read.
So cubing would be a good topic for essays? Did anyone write about cubing for his/her essays? It would be interesting to read.
I don't know if I have any great stories to tell about anything.

I'm a boring person.
Well, what topics would be good for you in a college essay again is a very personal choice. I did not write about cubing in my college essay... I did not cube back then. Cubing isn't necessarily about a single story, but likely an essay about cubing would be about the journey of discovery, exploration, and mastery, with a punch-line of 'with hard work, the human mind can truly accomplish anything'.
Thanks for the advice! Well, I still have a few months to think about it...
Edit: By the way, the SAT essay question was
"Does being ethical make it hard to be successful? Plan and write an essay in which you develop your point of view on this issue. Support your position with reasoning and examples taken from your reading, studies, experience, or observations."
For one paragraph, I wrote about Ville and Rowe claiming the BLD WR without peeking. Ethical and successful.
For another paragraph, I wrote about the Ponzi scheme.
Another random edit:
I just realized that I failed to spell "Bernard Madoff" correctly.

I don't think that affected my score.