Having a party? Hosting an event? or just want to send a message to someone in a unique way? Use POSTCARDS! You can choose to use video or just audio and send them to anyone with an e-mail address.
There are some hardware requirements. You need a microphone to make an audio postcard and both, microphone and camera, for video postcards. Many newer computers have them built in, at least a mic. Don't be intimidated if you need to buy these. They're relatively cheap now and there's no software to downlad, you simply plug them in and record!