Now, I know we all want to get a glimpse of what's going on behind the gates at Area 51 but that's not going to happen anytime soon. The government is pretty intent on keeping its secrets and we don't have access to any kind of cloaking technology to get in there without being detected.
No, these rare sights aren't of the closely-guarded-and-enforced-by-guns variety — these are more like things you just don't expect to see every day, or even every other day. But they're all things well worth grabbing a pic of.