iOS/Android/Web: Previously mentioned Sworkit -- the app that generates randomised exercise routines based on your timeframe of choice -- just added custom workouts. That means if you're injured, pregnant, or don't want to disturb the neighbours by jumping around for 20 minutes, you can find a plan that works for you.
The app always generated semi-random workouts to keep things interesting and fit within your timeframe, but this latest update really gets personal and helps you avoid working out when your circumstances change. Ryan Hanna, Sworkit's developer, sent me an email about the new features in the latest release, which I think perfectly explains why it's such a good one:
Some of the greatest experiences I have had with this project are the stories I get from users about their specific situation, and how Sworkit has been able to help them like no other app or workout has. Just a few uses for custom workouts that I have heard include multiple people recovering from injuries, women looking for a safe pre or postnatal workout, users that want to respect their neighbours by not jumping up and down, outdoor fitness goes who prefer not to lay on the wet ground, office workers hoping not to freak everyone out, and more advanced users who are looking for the toughest workout possible. The main goal of Sworkit has always been to help people workout by eliminating any excuse they ever have.
If you want to give it a try, you can do so for free on Android, iOS, or the web. Sworkit Pro offers a few more features, so if you'd like you can pick it up for $1.