I was thinking the exact same thing. I was really excited when I discovered codeEval, but after solving a few of the 'hard' challenges on there it became clear

I was thinking the exact same thing. I was really excited when I discovered codeEval, but after solving a few of the 'hard' challenges on there it became clear to me that hiring managers were looking for more well-rounded programmers with demonstrated experience in software development (something I've been working on through my own post-academic studies), not someone who can whip out a solid recursive algorithm to solve a brain teaser. And it makes perfect sense to me, the former is more likely to be actually useful in the day-to-day of a software engineering position, and the latter might only come in handy once in a blue-moon, or for more mathematics heavy domain-specific positions that require less code ejaculation and more optimization anyway.