Backpack customer Rizwan Reza writes in:
Backpack Tip: Send attachments to a Backpack page...I have come to use this on a regular basis now. Have some attachment in your email you want to save in Backpack, just email it to your page's email address, and magically, you'd find your message along with the attachments! Super handy!
Learn more about how Backpack can quickly turn your emails into notes, files, to-do lists, and photo galleries at the Tour: Backpack and Email page.
For example, this...
...becomes this:
Have a tip for other 37signals customers? Let us know.