You're right! Previously users could create an event without creating an account, but I was worried that people would abuse the system. Therefore I added mandatory accounts and email verification. Thanks for the feedback.
That said, awesome app. It's certainly a problem I'm sure many are constantly faced with. (I know I am) My first impressions though include a lack of detailed info (how does it work?) compounded by the inconvenience of making an account for the site. (I still haven't registered)
Edit: As for a small change you can do right away, I feel like users would consider "John Doe" <jdoe@example.com> more intuitive than "Invite Name" <Invite Email>. (Consider making the name optional altogether or just having a more intuitive input method, like multiple <input> prompts)