Noontime ice skaters are the people who carry bulging canvas bags to the Mall and take out their boots when they get to the Sculpture Garden rink. They're the men who skate in business suits, looking like La Nicoise waiters without trays. This season, another rink has opened up downtown for people who like their lunch on ice. Joining the Sculpture Garden and Liberty Plaza is a rink at Pershing Park, the redeveloped section of Pennsylvania Avenue between 14th and 15th Streets NW. Pershing Park opened officially in May. In the warm months, it's an island of honey locusts and a cascading waterfall. For the winter, the waterfall's pool has been converted into an ice rink. "The whole idea is to attract people there year-round," said Geri Porter of the Pennsylvania Avenue Development Commission. Terraced seating encircles the rink. In the kiosk at the eastern end of the park, a snack bar serves lunch, and there's an indoor cafe downstairs if it's too cold out for a picnic. A mumbling -- a muffled, barely recognizable Christmas carol -- makes its way into the air near the Treasury Building and hovers above the Avenue. From the construction site across the street emerges the occasional spectator in hardhat, but Pershing Park is a low-traffic oasis a block from the F Street shopping strip. The Willard looms overhead; no one looks out from the empty windows. A man and a woman skate slowly around together, she leading him a little, as in the scene in "Rocky" where Rocky and Adrian have talked a rink manager into letting her skate after hours. The wind gusts, the kind of wind that, if you spread your arms like wings and glide, pushes you speedily into the wall. The cold is the necessary evil of skating; for this rink to be open, said Porter, the temperature has to be 50 degrees and falling. The wind makes it a slow day: The rink guard says they usually have eight or nine people at lunchtime.

THE ICE DOWNTOWN PERSHING PARK -- Pennsylvania Avenue between 14th and 15th Street NW. Weekdays from 11 until 9:15, with a moonlight session from 9:30 to 11:30 on Fridays; Saturdays and holidays from 9 a.m. to 11:30 p.m.; Sundays from 9 to 9. One-hour weekday lunch sessions are $1.50; two-hour sessions, $2.75 for adults, $2 for children; skate rentals, $1.18 plus tax. 737-6938.

SCULPTURE GARDEN -- Constitution Avenue between Seventh and Ninth Streets. Weekdays from 11 until 9:30, until 11:30 on Fridays only; Saturdays, Sundays and holidays, 9 a.m. until 11:30 p.m. Weekday one-hour lunch sessions, $1.50; two- hour sessions, $2.75 for adults, $2 for children under 12; skate rentals, $1.25. 347-9042.

LIBERTY PLAZA -- 17th and G Streets NW. Daily from 11 to 8. Admission $2.50, skate rental $1.25. Weekday lunchtime special, 11 to 1: admission $2; skate rental $1. 377-6598.