Evite seems to be the standard for sending event invitations by email, but it has its annoyances. Mobaganda makes invites dead simple. Head to the site and type in the basics of your event. You’ll get a unique page thrown together for you, which you send as a link to guests via email (or Twitter, or text, or whatever you prefer). They arrive, answer yes or no, and you keep track of replies via RSS, or just checking the page. It’s an elegant alternative to sending sometimes goofy themed emails with no information in them.