Bring your four-legged friends—in costume if they’d like—to roam Old Westbury Gardens during ‘Dog Days.’ Twice a year canines are welcome to accompany their (leashed) humans around the grounds of the mansion, and this is Fido’s last shot until spring. On Sunday, enjoy exhibits from rescue groups and animal welfare organizations from 1 to 4 p.m. A dog costume contest and parade takes place at 3 p.m. All activities included with admission: $8, $5 for seniors and $3 for children ages 7 to 17. At 71 Old Westbury Rd., Westbury, Saturday, Oct. 25 and Sunday, Oct. 26 from 10 a.m. to 5 p.m. Tel: 516-333-0048.