(idea) by rfc1394 Thu Apr 19 2001 at 21:19:09
An old mnemonic used in astronomy to indicate the classes (or colors) of stars, or OBAFGKMRNS. The last three classes (RNS) are no longer used.
The more common usage is now via the mnemonic Oh Be a Fine Girl Kiss Me, or OBAFGKM.
I like it!