drop database??? No seriously, add disk or archive data are really your only viable options (maybe cleanup any unneeded "temporary" work tables?). Obviously, archiving data is going to require some sort of planning and, of course, testing of the process. Adding disk, depending on your server and it's setup, should be relatively easy. Never put yourself in this situation. Monitoring database growth and doing capacity planning is part of the DBA world. Never put your company, or your job, at risk by not being proactive.
-- You can't be late until you show up.