For people who don't know programming:
You can enjoy some minigames, full games (on some cases) and variety of apps the community made for free (and you can make your own if you know programming). Also, you can check their code and learn from them.
Thing is that you need a key (code) to download them. You can ask for keys here, like this picture of a BETA game i made.
2そうだね プレイ済み