A lighthearted and subtly derisive expression used to point out a sudden and profound shift in a person’s behavior, when someone does something entirely out of character.
Suddenly, after a lifetime of being late to everything, I found myself arriving solidly fifteen minutes early to all of my appointments, so I began to imagine I may be just one of the many folks who are channeling aliens!
Channelling is a concept in spiritualism where a person allows their body to be used by the ghost of a dead person, who can then talk to the others present through them. In casual speech, "channelling someone" means imitating another, acting, talking or thinking just like that person.
Obama: "Whoops, I slipped and accidentally said I wanted us to export more jobs - I was totally channelling Romney there for a sec."
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.
A lighthearted reaction upon receiving disappointing news of some sort. Usually something that isn't a particularly a big deal, esp. when it primarily affects someone else - sort of a mild schadenfreude. Sometimes doubled or tripled, and possibly said in a sing-songy voice for added comedic effect to imitate a muted trumpet, which is how the meme originated.