i'm not awesome at being athletic, but i recently got into climbing through some friends of mine.
i've been to boulder's only a few times, but i found it nice, clean and friendly. there are a good number of climbing walls, equipment to rent and instructors to help.
tuesday night is college night so it's only 8$ for belay-certified climbers and boulder-ers. also, another option for cheap climbing is to go an hour and a half before close (also 8$).
in addition, there are classes, party opportunities and a climbing team.
*note* the last time i went on college night it was fairly crowded and hard to find a wall (although part of that is because i'm picky about what paths to climb). i don't think this is always the case but it was a little daunting for a beginner-climber.