Actions or behaviour befitting everyone's favourite cartoon sponge such as blowing bubbles, hollering "I'M READY!", being unreasonably enthusiastic about your job & making up & singing songs on the spot.
Spongebobbery can fall just about anywhere on the spectrum of good & evil.
Example 1:
Person A: Hi, Person B! What are you doing today? I'm going to work four shifts back to back! I can't wait! Today is the best day ever! I'M READY!
Person B: What Spongebobbery is this? Go away!
Example 2:
Person C comes upon Person D blowing bubbles with alarming skill.
Person C: What Spongebobbery is this? Can you give me a bubble blowing lesson?
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.