Wikipedia on Athenian Ostracism
Each year the Athenians were asked in the assembly whether they wished to hold an ostracism. The question was put in the sixth of the ten months used for state business under the democracy (January or February in the modern Gregorian Calendar). If they voted "yes", then an ostracism would be held two months later. In a roped-off area of the agora, citizens scratched the name of a citizen they wished to expel on potshards, and deposited them in urns. The presiding officials counted the ostraka submitted; if a minimum of six thousand votes were reached, then the ostracism took place: the officials sorted the names into separate piles, and the person receiving the highest number of votes was exiled for ten years.
The two stages of the procedure ran in the reverse order from that used under almost any trial system — here it is as if a jury are first asked "Do you want to find someone guilty?", and subsequently asked "Whom do you wish to accuse?".
Reminds me of something…