I had to chuckle when I read this post on the Unclutterer blog. I forgot about it, but yeah, I have one of those. Well, not as fun as the one they posted about, but I do have a plastic knife meant for cutting lettuce. At least I can say, I didn't buy it. It was a gift... that's been in a drawer way too long.
A produce storage bin and a lettuce knife - both Christmas (or maybe birthday?) gifts from 2-3 years ago. I don't think I ever used the knife. I used the bin a few times though I really don't think it worked any better or worse than anything else I've used to store produce. It takes up too much space in the cabinet and I haven't used it even once since the move last July so... a few more pieces of plastic in the donation box!