Big event we covered for the Planetary Society (Planetfest 2012) in August for the landing of the Mars Curiosity Rover.
See here for a video featuring Bill Nye "The Science Guy" who is CEO of the Planetary Society. There are some slides.
http://bit.ly/VxyUeH Also check out the playlist on the link to other Planetfest videos which will have more slides than the Bill Nye presentation.
We had three cameras (Sony EX3's via HD-SDI) - we mostly just used two of them... with the third for an extreme wide shot of audience on occasion. Then we had Bluray (via component) / direct HD downlink of NASA HD channel via HD SDI, VGA input from laptops etc etc.
We had about 26,000 live simultaneous viewers for the event across two days.
Gear used includes
ATEM 1/ME which was in 720p5994 mode.
ATEM TVS (used as a backup... in case something went wrong... which it did...not the fault of the 1ME... but the locations power went out and destroyed their routers... I was unable to reconfigure the 1ME to work with new IP addresses as the switch was being used to drive the venue's projectors for the live audience... so for a while I switched in the TVS to handle the streaming until we could bring the whole system down during a break and reconfigure everything)
Program recorded onto Hyperdeck Studio in ProRes
Used every Black Magic converter/adaptor I had (HDMI to SDI, SDI to Analog) and other adaptors (Gefen Toolbox / Atlona VGA to HDMI scaler) - plus Apple TV for skype connections via an iPad with folks in New Zealand and other places.