I've been fantasizing recently about a "Magic Wand" computing device. The thing would be as small as a laser pointer and have little to no UI. The wand could detect nearby presentation resources, have a tiny (audio/light) indicator of availability, and could send a few simple messages to these devices. Using the directed connectivity (IR) a user could easily specify gestures for specific devices. Combine with Wi-Fi, TCP/IP, a little local storage, some computing and you've got a device that a person can do "ad hoc" interactions with.
A Pocket PC device with a Total Remote attached might fit the bill. Not quite as small as a laser pointer, but good enough for a proof of concept. The Magic Wand eventually should be a fixed function device, but for prototyping a general purpose computer is good.
Or maybe I should just look at the X10 stuff. But the key bit is that I *really* want good old TCP/IP and the new overlay multicast that's really going to change the Internet. And I expect the presentation resources to actually be a bit smarter than your typical X10 device.
Memo to self: they're only 30 bucks, buy one already!!