I consoled a despondent friend over text message while I was extremely busy at work with a time-sensitive project. The conversation lasted 8 hours with only a few minutes in between each text. It was one of the best, most cathartic conversations I've had over text in years. We laugh, cried, and grew closer.
Eh, don't really know that I could call this a "good deed," but I'm glad that I took the time to talk to a friend when they needed me.