Expenses incurred while a Reservist, Performing Artist or Qualifying Government Employee are subject to special deduction rules. The amount entered is deductible whether or not you itemize deductions.
If you are an Armed Forces Reservist, you are able to claim a deduction for amounts attributable to travel more than 100 miles away from home. The travel must be reserve related.
If you are a Fee-basis state or local government official, include any amounts attributable to the expenses you incurred for services performed in that job.
If you are a Qualified Performing Artist, include any amounts attributable to performing-arts-related expenses.
The qualifications for Performing Artists can be found here.