Asana is an incredibly useful task manager. It’s my main to-list app on both my phone and computer. They have recently added a number of integrations to make the app even more useful.
I have not done much with this beyond the Google Calendar integration, but I’ll be keeping an eye on this page to see what developers end up doing with this API. I hope IFTTT adds an Asana channel. Connecting my to-do list to the rest of the web could introduce some interesting possibilities.