RICHARD SCARRY doesn't include it in his popular children's book. "What Do People Do All Day?" but one answer in this city -- at a salary of $17,000 a year in public money -- is "little or nothing." That is what two D.C. government employees turned out to be doing when Post reporter Art Harris followed them around for seven randomly selected days during the last two months. The two were supposed to be inspecting roofing, but they were checking out almost anything else around town instead -- cruising in their government van, running personal errands, dawdling in a topless-bottomless joints and otherwise killing time at taxpayers' expense.

But Mayor Barry didn't waste any time a all when he read this story. That day (well before quitting time at the District Building), the mayor fired the two men, ordered a full investigation of the agency that had employed them and reprimanded their department head. Is that any way to treat a group of local government employees? You bet it is -- and more power to the mayor for it.

Throughout local and federal government, the standard reaction of the person allegedly in charge is to 1) mumble something about "looking into the matter" 2) wait until people forget to ask about it anymore, and 3) slip the offender-employee(s) into other government jobs paying as much or more as before. If the matter ever does come up again, the response can include a mealy-mouthed statement on the difficulty of doing anything what with civil-service regulations and all.

But to his credit, Mayor Barry says that whenever cases like this are brought to his attention, he won't horse around. This doesn't mean disregarding legal job protections for civil servents. It is exercising control. It is also one way to clip the overstuffed payroll in these tough financial times. Come to think of it, maybe taxpayers all around town should start monitoring government employees and sharing the findings about exactly what government people really do -- or don't do -- all day. It might do wonders for the budget.