Here's one way: go to http://netnewmusic.net/ and choose a name at random from the right-hand column. If the name selected is familiar, reload the page, and try again.
Here's another way: go to the birthday page at the American Music
(Note: the NMB's birthday list is limited to US composers (and even then, at least one day in September is deficient by at least one expatriate Californian.))
Today I got to learn a bit about: Alexandra Gardner and Ludmila Ulehla.