Galactic Darwin Award

Ways in which Earth may win the Galactic Darwin Award. Background of Earth's version: (http://en.wikipedia.org/wiki/Darwin_Awards)

LHC decides to experiment with mini black-holes, which turns out don't stay mini.
Elect Sarah Palin, and give her and her family inadvertent access to The Red Button.
Differently-Staffed Repeat of http://en.wikipedia.org/wiki/1983_Soviet_nuclear_false_alarm_incident
- (Thank You, Mr. Petrov! A true hero.)
- There have been other similar close calls. I don't know if we are lucky or a product of the AnthropicPrinciple.
SETI or NASA probes notify galactic terrorists of our existence by sending a friendly "Hello". The terrorists may be offended by nude images on Pioneer 10 or 11's "Hello" plate, or believe the Voyager song samples are "works of the devil".
Some dumbass Sheldon-wannabe discovers in their garage that they can create a new universe out of a vacuum...with the side-effect of destroying anything within a few light-years.
Inadvertently allowing AI to take control by using its own efficiency in R&D to outsmart us: TheSingularity

Non-Qualifying Honorable Mentions:

LHC discovers that we live in a "false vacuum" by triggering the true vacuum - http://en.wikipedia.org/wiki/False_vacuum
- Disqualified because if true, there would be no galactic authority left to hand out the prize