It's been a long time since I've seen Once, but it's a touching love story. As far as I remember, there's no violence, graphic sex or anything remotely objectionable or disturbing besides your aforementioned f-bombs. The R rating may not be shocking since we know how the MPAA rates thing, but it certainly doesn't make sense that Once is less appropriate for teens than movies containing violence, sex and other things parents typically object to their kids seeing. Here's the top grossing PG-13 movies: http://boxofficemojo.com/alltime/domestic/mpaa.htm?page=PG-1...

I think you'll find Once to be more innocuous than almost all of the movies on that list.