The first major release for the FOSS game engine in some time, CorsixTH 0.63 is out following the recent release candidate build. CorsixTH might not be "finished" but it's incredibly playable and does provide a better experience (mostly) over running the original Theme Hospital.
With this release the game music now supports more file formats like ogg, flac, wav, aiff, voc in addition to mp3 and midi. Additionally, you can now save your camera position to easily jump back to it, announcements don't overlap and use a queue system now, hotkeys can be configured making it much nicer for different keyboard layouts, you can adjust the scroll and zoom speed and there's of course the usual assorted bug fixes. You can find the full release notes here.
As a reminder again, CorsixTH requires you have the original data files which can be grabbed easily enough from GOG.