Dolphin is a Gamecube, Wii and Triforce (the arcade machine based on the Gamecube) emulator.
Gamecube compatibility is okay-ish – lots of games work, many games don’t work.
Wii compatibility is not quite as good as the Gamecube compatibility, but many games are playable, and lots of games are showing intros and more.
Triforce compatibility is not really known yet, but at least one game runs, with minor glitches.
This is a working Wii Emulator with a lot of people involved in the project!