Sometime after the engagement is formally announced, it's customary for the bride's parents to host a party. Usually, it's held just before your announcement appears in the paper, or soon after. Invitations can be formal, informal, or even made by phone. Likewise, the event itself may be small or large; a casual barbeque, or a fancy dinner out. It's really up to the hosts, and the couple. Still another option is for the couple themselves to throw a party, then surprise everyone with the news of their engagement. It's fine to have more than one engagement party; often, the groom's family may throw a second event, so they can celebrate with their friends and relatives. While gifts aren't expected, some guests may want to bring them anyway...so let your parents know where you're registered, in case people ask. Be sure to send thank-you's right away, for any presents you do receive. It's also nice to send a thank-you gift to your hosts for the party, even if the hosts were your parents.