Roald Dahl
That's what Glee reminds of.
I've been trying to put my finger on it for so long. It's the mixture of over-the-top facetious melodrama (Sue Sylvester as Madonna!) and the we're-serious-here realism they keep trying to combine (and now girls an important lesson on eating disorders!). While I don't think the show writers manage to integrate the two very well, they keep walking the line between the two and it keeps reminding me of Roald Dahl more than anything else.
I mean, come on, Sue Sylvester = Miss Trunchbull, yes? The comparison just begs to be made (well it does to my mind, anyway) when she physically pushes the students out of her way and generally acts like the typical Roald Dahl adult villain who mistreats children. All that's missing really, is the grotesque violence. (I really, really want her to swing a girl round and round by her pigtails and throw her out of a window. Or make Mercedes eat a whole chocolate cake - it's totally consistent with her cartoon villain personality.)
And of course, Mr Shue is the "good" adult figure on the side of the kids.
All they need now is some macabre scenarios and a little more dark humour. And some Quentin Blake illustrations.