Sentence:  At a recent <WSD>nerdfest</WSD>, where it was decided Pluto wasn't a real planet, one of the scientists held up a stuffed Pluto (the Walt Disney kind) and an umbrella, and wittily pointed out that Pluto was under the umbrella of planets that include “dwarf planets.” 
Meaning of the word marked with <WSD> tags:  A gathering of nerds or an event centered around the interests of nerds.