"Mostly in reply to the above post, Happy Feet had my friend and me unashamedly dancing out of the cinema! We were the eldest there (at 18 and 19), but after some initial "It'll probably be bad, but, hey, penguins!!" we really got into it (both being musicians).
I won't say that, as university students, we have the cleanest minds on Earth, but I noticed nothing dirty or drug-related about it. Sly inuendo is for keeping adults entertained (and to be sure, I remember chuckling when it went right over the kids' heads) - and without some distinguishing features, how would we tell the penguins apart? They are so remarkably similar in real life, so all credit to the animators for making them so wonderfully individual!
One last thing- although the ending was a little hurried, everyone I know who saw it agreed it was a lovely story and even if it was not your cup of tea, it is worth seeing merely for the stunning animation. This film mixes 'real' film, real people, with animation, and I for one can't tell where the 'real' images start and the animated ones end..."