3rd Rock from the Sun - Season 4 Episode 12

When Harry's boss Doug starts deducting income tax from Harry's paycheck, the Solomons realize that they have never filed a tax return and that they owe $9500 to the government. To combat this, they invent the 'brilliant' notion of lying on their tax return and Dick reworks the sums so that the government owes them several hundred thousand dollars. Sally attempts to help by setting up a failed home hairdressing business, but when women start arriving for haircuts, Harry and Tommy 'camp up' and take to the 'salon' to help. Lying doesn't work, however, and the Solomons are faced with an audit - and the threat of being exposed as aliens.