I made a multiplayer game about building a shared language, called "The Yelling Game." Here's a video of people playing it.
It ended up winning I forget what the prize was called, but me and Adam Rickert, the artist, both went home with three-cube Sifteo sets.
This is probably going to help nobody, but if you want to play it and you know what to do with an ELF, here's an ELF. Enjoy!
Overall I was quite impressed with Sifteo as a platform. The specs are shockingly restrictive by modern game developer standards, but the SDK is very slick as embedded systems development goes. Daniel Plemmons, the guy who ran the jam, told me that part of his job description is to run a jam like that every two months. I'm probably going to make a habit of attending, because this was a lot of fun.