Send Obama a bitcoin and let him mention it on tv.
Nice, but how do we get him a wallet address?

You could send Obama a tip on @changetip. They will set up a wallet for his twitter account, which he can claim if he chooses.
Nice! I just signed in and they gave me 50c for free. If many of us tip the same person it might get attention. I what about Colbert or similar? I'd imagine he'd be more open to mentioning it and getting some more momentum with it?
@madbitcoins tried to get a mass tipping to Youtube celebrity Jenna Marbles a couple of weeks ago. She didn't respond/collect the bitcoins and after a while it looked like borderline Internet stalking. I'm not sure any celebrities (other than some of the more tech savvy like Tim Farris, Mark Cuban, etc.) will take the tip and start talking about it. Joe Rogan has had two podcasts on it, but that was back when it was over $800.
I don't think we need celebrities mentioning bitcoin for it to be know to the mass public. Bitcoin is well known enough so that most people have at least heard about it, but probably don't know what it is/how it works. It has made the news many times, and there has been the misconception that bitcoin has "filed for bankruptcy" many times. What needs to happen is for the public to be better educated as to how bitcoin works.