Smartphones, tablets, computers--they're all just tools designed to allow humans to accomplish something important to them in the real world. Complaining that your iPhone is no longer sufficiently entertaining is like whining about no longer being fascinated by your hammer.
Go out and find a goal to accomplish: learn a foreign language, bird calls, astronomy, ham radio, backpacking, weightlifting, travel, gardening, anything---there are apps for all these real-world interests and for dozens more. Better yet, find something to do with your time that makes somebody else's life better--find a charitable organization to volunteer for--the Scouts, your religious institution, Habitat for Humanity, Livestrong, Goodwill--they all need volunteers, and any of these activities will provide plenty of opportunities to use your gadgets to enhance your effectiveness.
When you're using technology to help you accomplish something important to you you'll never be bored using it; if you use technology simply to see what it can do that the technology of the day before couldn't, you'll always become bored.
It gets to be like taking a thirteen year-old into a toy store--he loves the idea of going there, he walks in all excited about replicating the thrill he always used to have when receiving a new toy, but soon enough he begins to realize that play toys are just not so fascinating anymore. And that's when you know that your little boy is growing up.