Google Wave takes the functionality of email, instant messaging and apps, and rolls them all into a single open source tool. There is a full demo available with a few jaw dropping ah ha! moments.

• inbuilt instant messaging in all your email conversations
• instant messaging that can translate into other languages as you type (perfect for communicating with international academics)
• an inbuilt spell checker that far surpasses anything you've ever seen
• insert applications (eg google maps, photobucket, twitter) into your email and IM
• search and insert links into your email/IM as your write
• discuss and collaborate on google docs in real time
• create surveys and polls and analyse the results, all within email/IM process