As others have pointed out, Minetest itself is basically just an engine. To have actual fun, you need to download a "game" for Minetest. There was a big debate on the Minetest forum some time ago, discussing whether Minetest should come with a game preinstalled or not. Reason being, new players are usually not aware of game modules and default Minetest - let's be honest - is kind of boring and tends to drive them away. Personally, I feel like this is still a problem. But anyway.

Give Lord of the Test a shot. I've had reasonable amounts of fun with it. It's not Minecraft, but rather its own thing. I rather liked it.