And to think, I almost made a pit stop on ck's pool before switching over from slush. Was thinking about going at it for 24 hours or so. It's all good though, I'm happy to have found a block for the pool, and I wouldn't necessarily have found one on ck's pool. (right?)
Of course you could have found many more on solo or none.
Yep it's random with a bit of poisson distributed luck thrown in
tl;dr;
X ~= hashrate * Y / 2^32;
Here Y <= 30