throw your hat into the ring

Meaning

1. to announce officially that you are going to compete in an election, a competition, etc.

From the same entry

• go hat in hand
• keep under your hat
• my hat
• out of a hat
• I take my hat off to
• at the drop of a hat
• I'll eat my hat
• knock into a cocked hat
• pass the hat round
• pull rabbit out of the hat
• talk through your hat