If you aren’t familiar with Unity, it’s a free game engine with a built-in game editor. I use Unity almost every day, and as you can imagine, I’m coding a lot. Now, when you are writing the majority of code for a game, you are testing things out. Perhaps you want to see how fast is fast enough, or how far is far enough. It can be a pain to enter and exit play mode constantly, but wait!
Unity has a nifty little feature that will recompile code and execute it, even while in play mode. You can easily switch over to Visual Studio (or MonoDevelop) and save your changes. Then you can “Alt + Tab” back over into Unity and quickly see your changes. The only downside to this is that, with large projects (10,000+ lines of C#), this can take a few seconds–even on a really fast machine. However, it’s invaluable when testing things, as you never have to leave your spot in play mode. 😉