In poker, the ante is the money each player puts in the pot before the hand begins. Hesitate to add your cash and the dealer will likely shout "ante up!"
There's "ante up" and then there's "up the ante" — both idioms that have seeped out of the poker world into everyday speech. The former means to pay up; the latter means to raise the stakes or make something either more risky or more desirable. Parents can really up the ante by promising their kids a trip to Disney World if they bring home all As at report card time.