The US Constitution states that two-thirds of the states need to ratify an Amendment to become the law of the land, but there is no expiration date to this ratification (see Coleman vs. Miller). The 27th Amendment (the Madison Amendment) is the latest Amendment to our Constitution which became law in 1992, but it was originally introduced to Congress by James Madison 203 years before. Madison wasn't president yet; he was a Congressman at the time.
The 27th Amendment is not very interesting or controversial. It basically states that Congressional pay raises can only be granted directly after a House of Representatives election. So after a increase is voted in, an election must take place before it can go into effect. Six states originally ratified it: Maryland, Vermont, Virginia, Delaware and the Carolina's. At the time, 10 states were needed to make it a law. Ohio ratified it in 1873 and Wyoming in 1978. It wasn't until 1982 that it started getting wider recognition by the rest of the states. An under-graduate student at the University of Texas, Austin, Gregory Watson, started a letter writing campaign to get the rest of the states to ratify it. It took ten years. On May 7th, 1992, Michigan and New Jersey became the 39th and 40th states to ratify the Amendment. There are still five states that did not ratify it: Massachusetts, Mississippi, Nebraska, New York and Pennsylvania.