There's no time like the summer to get active, and Penn Recreation Department classes offer you the chance to do it with experienced instructors. This summer, Penn Recreation offers sports and fitness classes for all ages:

• AEROBICS: Classes in step aerobics, cross-training, conditioning, high- and low-impact aerobics, and "aerobox" (aerobics and boxing) run from June 1 to July 31 in Hutchinson and Gimbel Gyms. Fee $85, faculty/staff $75, students $45. Call the Recreation Information Hotline at 898-6100 for specific class times and locations.

• BOXING: A beginning-level course emphasizes footwork, blocking and punching techniques, and cardiovascular development. 4 to 5 p.m. Tuesdays and Thursdays from June 2 to June 25 in Hutchinson Gym. Fee $80, students $45; equipment costs $70.

• CHILDREN'S SWIMMING: Beginner, intermediate and advanced classes for ages 6 to 12 meet from 10 to 10:50 a.m. Saturdays, from June 6 to Aug. 15 in Hutchinson Pool. Fee $100 for one child, $180 for two and $240 for three.

• GOLF: A four-week course teaches the basics of golf. Two sessions: 2 to 3 p.m. Mondays from June 6 to June 22 and 1:30 to 2:30 p.m. Wednesdays from June 3 to June 24 on Hill Field. Fee $75, students $45. Equipment recommended but not required.

• SCUBA DIVING: This course teaches basic skills for scuba and open-water skin diving. 3:30 to 6:30 p.m. Mondays from June 1 to July 6 in Hutchinson Pool. Fee $160; approximate equipment costs $295-$395.

• TENNIS: Eight-class sessions at the beginner and intermediate levels. Beginner classes meet from 4 to 5 p.m. and intermediate classes meet from 5 to 6 p.m. at Lott Tennis Courts. Two sessions: Mondays and Wednesdays, June 1to June 24 or Tuesdays and Thursdays, June 2 to June 25. Fee: faculty/staff $45, students $20.

• SWIMMING: Beginner, advanced beginner and intermediate classses meet from 11 a.m. to noon Saturdays from June 6 to Aug. 15 in Hutchinson Pool. Fee: faculty/staff $75, students $45.

• YOGA: This course teaches the method of Yoga Master B.K.S. Iyengar. Noon to 1 p.m. Mondays and Wednesdays from June 1 to June 14 and from July 6 to July 15 in Hutchinson Gym. Fee $80, faculty/staff $55, students $30.