The mysterious 1977 SETI radio detection known as the "Wow! signal" is finally getting a response from humanity via a project by the National Geographic Channel and Twitter. Tweets sent with the hashtag #ChasingUFOs June 29-30th will be combined into a single message that will be beamed into space in the direction of the signal on Aug. 15th-- the 35th anniversary of the 'Wow!' event. Further details here.