Le Jour des Lapins

I've recently encountered a phrase in French that I learned years ago and promptly forgot: C'est une bonne idée. Word for word, it means, That's a good idea. Very useful, common phrase, yes?

Unfortunately, I haven't yet been able to say it without snickering -- same thing back when I was in school. It's not that there's anything wrong with the phrase. The problem is, it sounds for all the world like C'est une bunny day when you say it aloud. And how can you talk about a bunny day without smiling?