A shopping list app, with all the regular features, but the cool thing about Out Of Milk is you can share lists, with your partner or your housemate. This means that if one of you runs in to buy say, Cornflakes and skimmed milk, then those items are taken off the joint list. You can also add additional details (like a preferred brand etc), and the pantry section shows you all the items you already have.
A cleaning app for lazy folk, with a lot of swearing. No, seriously, lots of swearing. If you don't mind that, then UYH sets easily accomplishable cleaning tasks, with plenty of time for scheduled breaks.
This app means that you'll never be late again. Calculate the most efficient route, or the most cost-effective, or a rain-proof journey. Available for: London, Paris, Berlin, Madrid, Barcelona, Milan, Rome. New York City, San Francisco, Chicago, Washington DC and Boston.
Short for, "If This, Then That". Create 'recipes' to save clicks. For example: I'm tagged on Facebook + save the image to my device. Or: I tweet an article from a newspaper + save it to my Instapaper. Nifty!
Make your *phone* more efficient. You can help to study diseases, predict global warming, or discover pulsars, by allowing the Berkley Infrastructure for Open Network Computing to run jobs using the unused computing power of your device. Basically this means that within parameters (like, when plugged in, on wifi, with a good battery life), your phone can collect, compute and transfer data for any number of scientific projects within the scheme. Cool!
Available on Android. For a similar thing on Apple, try Genes in Space a game which analyses genetic data for cancer research.