One of my favourite multimedia product would be the Nintendo Wii! I think it's amazing as it introduced real-time motion into the games and hence forever changed the way we play games. On top of that, one can actually connect to the internet using the Wii box and as such connect with people around the world who are also playing the same game (only available for certain games, though!).
Asides from game communities, Wii has been used in the education sector. Do you know that North Vista Primary School adopted Wii Sports into its PE (physical education) program?
I think this is an interesting idea, using wii sports for fitness. One thing that I realise from using it personally would be that many-a-time we tend to use more energy playing the game than we would in real life (think virtual tennis VS real tennis). We seem to sweat more, feel more tired when we're playing the game. I suppose this is good in a way that we burn more calories? But then again there's that concern about exerting ourselves too much hence injuring ourselves.
/edit:
and I just found out the existence of the game EA Sports Active.
Com 125, Class A =]