I was browsing through the collection of the MoDiP (Museum of Design in Plastic, which also have some nice rare walkmans in top-notch visual condition ), and found one of these. http://www.modip.ac.uk/artefact/aibdc-001808 A Sony PET-F7 Funbbit "virtual pet/music tamagotchi" in-line headphone/remote unit. Never seen it before, and it seems quite interesting. Not much info about it, and judging by that it doesn't seem to be a big hit, and perhaps was only released in Japan? I'm sure it won't bee that that interesting in terms of enjoying the analog sound, but definitely something interesting just for the sake of being unique? There's one on ebay right now, and it's not cheap. But the listing does describe a little of the actual "gameplay".
