Everything in this thread so far is way too easy.
Three gnomes were locked to three chairs. Each gnome has a hat on his head that is either white or black but cannot see anything. While gnomes remain blinded they can communicate with each other. Then, their blinds are removed and they cannot talk anymore.
Gnomes can then either guess what is color of their hat - mind you, they dont know what is their hat but what they do know, as they are no loner blinded see colors of other gnomes hats - or remain silent. If any gnome tries to guess and fails then all of gnomes die. If no gnome tries to guess they all die. The only way gnomes will remain alive is that at least one of them guesses his hat color correctly and none of them is wrong.
What tactic should gnomes take to have 75% likelyhood they remain alive assuming their hat colors are chosen randomly?