Exercise bikes are getting smarter all the time. Many of the new models not only connect to your iPhone but come with interactive classes. The Ovicx WEKEEP Fitness Bike is also worth a look. It works with the RebornFit iOS or Android app and comes with 4 classes with adjustable intensity.
The companion app tracks your training data and records all your stats, including time and calories burned. Live courses are available, so you will always have something new to try. You can use this bike with Zwift and Kinomap too. Its height and front/back seat are all adjustable.[where to get it]