[xorglorb]

Skype would seem to fit the bill.

[phillco]

That was my best guess too, and Skype is also ubiquitous and would be extremely difficult (popularity wise) to censor. But I doubt video data is truly random -- it probably has some structure to it.

[anthonyb]

Encrypted video/voice data looks like encrypted Bittorrent data.

[phillco]

Oops, forgot Skype video was encrypted. Duh. In that case it'd do fine.