Particle sim not rendering in Cycles - what am I doing wrong?

I have a particle system made of objects. In wireframe mode, it seems to be working properly. However, I don’t see the particles at all when I render in Cycles. Here’s the file: http://simplecarnival.com/blender/particle_problem.zip

Any idea what I’m doing wrong? I have a feeling it’s something simple. I researched as much as I could and I’m still scratching my head.

Thanks!

Ah, never mind. I figured it out. I needed to put the objects into a group and then use the “Group” setting in the particle system options.