Amida allows you to send email in your own handwriting, in addition to typed text. Not only is this fun, but it also means you can write mails in any language - Hindi, Tamil, Chinese... all supported. You could even sketch out (using a pen-like stylus) e-cards or maps and email them.

Amida also has a built-in voice recorder, so you can record and email your own voice too! (More about Email)