My friend Alex, founder and CEO of RTNP Heavy Industries, has created the world's best Android app, Don't Panic. Here's a screenshot:
It's so you have a little reminder at your fingertips, whenever you need it. I have no idea how to install it, not having an Android myself (though that might change given this app), but that shouldn't stop you.
It's only $0.99, less than 1/6 of a sandwich. Cheap! There's a free version, but it's not nearly as good. Shell out. You won't regret it.
Project 100, #43. (doh!)