Not that there's a bad time for pie, but with food writer and baker Lisa Lacy celebrating National Pie Day by giving away free slices from six different kinds of pies, today's an especially good day for sweet tooths. The tastings begin at 7 p.m. at Greenwich Village Bistro, 13 Carmine St., between Sixth Avenue and Bleecker Street; 212 206 9777. Admission is free while sup-pies last.