1. "put a ring on it"
1.a) to promise something as an engagement/wedding ring symbolizes promises.
Rochelle: Are you going to call me?
Fred: You Bet. Put a ring on it.
Rochelle: Alright
1.b)To marry someone, usually a woman. From Beyonce's song "Single Ladies."
"If you liked it then you shoulda put a ring on it."
-Beyonce, "Single Ladies"
2. "throw/toss your hat in the ring" (American & Australian)
to do something that makes it clear you want to compete with other people, especially to compete for a political position
She's seriously considering throwing her hat in the ring and declaring herself a candidate for the election.
3. "the brass ring" (American)
success or a reward that you try to achieve, often by competing against other people
Our aim is to have the best team in the league - the brass ring is there guys, go and get it.
References:
http://www.urbandictionary.com/define.php?term=put+a+ring+on+it
http://idioms.thefreedictionary.com/throw+hat+in+the+ring
http://idioms.thefreedictionary.com/the+brass+ring
