I've thought about giving people an old Fortran project with a few small compile errors, and asking them to fix that. We're not using Fortran of course – it's just a test of pragmatic skill of Getting Shit Done™ without hand-holding.
Inspired because I had to do exactly the above a few months ago. I don't really know Fortran. I don't even know exactly why it failed to compile, but my fixes work (and verified to work correctly), so whatever. I just read the compile error, copied what other bits of the code do. Basic stuff really, but it would probably filter out the worst of it. I haven't put this theory to the test yet though.
Inspired because I had to do exactly the above a few months ago. I don't really know Fortran. I don't even know exactly why it failed to compile, but my fixes work (and verified to work correctly), so whatever. I just read the compile error, copied what other bits of the code do. Basic stuff really, but it would probably filter out the worst of it. I haven't put this theory to the test yet though.