From the Perpetual Kid website, from whence you may purchase the Finger Food Party Plate:
Fortunately, we’ve got the answer… these charming little plates with rings that fit right on your finger. Now you can balance your glass and your hors d’ouevres, and look positively in control the whole time. Genius!
I think, technically, they were answering a different question than I was asking, but it still worked out pretty well, don’t you think?