A couple of years ago, I wrote a small plugin for Outlook Mobile (the version of Outlook that you get on Windows Mobile phones) to help me triage my emails.
The idea was to make it quicker to process my email from my phone, by adding a couple of context menu items to emails that let you create a new To Do item in Outlook Tasks, or a new diary entry in Outlook Calendar.
So if someone sends you an email asking you to do something, with one tap you can create a new To Do list item, pre-filling it with information from the email.
And if someone sends you an email about an event or meeting you need to go to, with one tap you can create a new Calendar item, prefilling it with information from the email.