My community theatre is doing a Funny Thing Happened on the Way to the Forum, with auditions in a couple of months. I plan to audition and think that Philia is the role I'd like to aim for since I think it would be the best suited to me (though I'd be happy doing anything, really).
I want to get a song really well prepared for the audition, so I want to start working on it now, but I'm at a loss for what to pick. I've heard the suggestion to try other songs by Sondheim, but I'm not sure quite what.
I want something that will be fun and somewhat lighthearted, but allow me to show some acting skills, as well as show off my voice (soprano).
They haven't announced any specific guidelines for audition songs, but you can usually do just about anything and if you bring sheet music, they provide piano accompaniment.
Does anyone have any suggestions for good audition songs? Any suggestions in general for auditioning for the role?
Thanks!

Consider songs by the following Sondheim sopranos:

Cinderella from Into the Woods
Johanna from Sweeney Todd
Anne from A Little Night Music

Though I wouldn't say that all three are intrinsically light-hearted. They just come to mind most easily.