Who's on Twitter, Vol. 8

There are more than 500 million people on Twitter. Some of them are teens. But some of them are famous people! And since we can't all be Justin Bieber, Celebuzz is paying tribute to the decidedly less high profile users of Twitter. Gary SiniseAge: 58Occupation: ActorTwitter Handle: @GarySinise When's the last time you thought about Gary Sinise?...