1) Put to pasture
-This woman has already become a grandmother, let us put her out to pasture to take care of grandkids.
-It is terrible to put someone in their 50s out to pasture, because they have little chance of finding a new career.
-My grandpa refused to put to pasture even in his late 80s.
Definition: to retire someone.
Etymology: to retire a horse by allowing it to live out its days in a pasture with no work.
2) To get just desserts
-I feel better now that Janice got her just desserts, she really insulted me.
-Did you hear about the Royal Princess who was robbed, she got her just desserts.
-The annoying guy got a really tough instructor, he got his just desserts.
Definition: to get what one deserves.
Etymology: It should be noted that the use of desert in the sense of to deserve has been in English since the mid-13th century. so it is just a misspelling.
3) Till the fat lady sings
-Although the race contestants were far beind, it was not over till the fat lady sings.
-The Meredith Kercher murder trial won't be over until the fat lady sings.
-In football, even if there are only a few minutes left to tie up the game, it is not over till the fat lady sings.
Definition: at the end; a long time from now.
Etymology: Supposedly from a tale about a child sitting through an opera who asks a parent when it will be over. "Not until the fat lady sings" is the answer.