I must second this. Godot is… well, it's hard to believe it's actually a free and open-source project. It's a cross-platform 3D and 2D game engine with a fully integrated development environment (including a friendly visual editor for 3D and 2D scene graphs) and its own custom scripting language. Akin to Unity 3D in the proprietary world.

I decided to try it out this week to make a (3D!) game, and I've been consistently surprised by how pleasant an experience it has been. The community's been helpful when I've had problems, too.