Ok it's not people inflating but makes for an interesting idea. A webcam is hooked up to a room full of space hoppers, the space hoppers are slowly inflated by people tweeting #pumpt.
Well something gets inflated for you on request very slowly. There are also technicans than tend to the space hoppers and make sure they blow up okay. It's only there for another week or so, so go check in soon:
http://www.sonyericsson.com/hopperinvasion/warehouse.aspx
Posted the wrong thing, as it wouldn't let me reply straight away.
But imagine if it was people in inflatable suits being gradually inflated instead. You could probably choose who you inflated.