Launcher runs fine.
Login works fine.
Force-Update works fine.
After that, black screen. No Mojang icon, nothing.
This does not appear to right itself.
Worked fine before, only had the problem on 01/11/2012 (NZ, GMT +12).
Restarting computer did not work.
Only possible problem that I could think of was that the 'fullscreen' and 'vsync' options were causing problems, however resetting them in 'options.txt' did not fix.
Similar problems have been experienced before, however they either fixed themselves at the next run, or after time, or after restart.