I have received several blank e-mail from various members with bizarre topics.

This is a tell-tale sign of the Klez virus. Go here for a removal tool and information on the virus.

In short, one aspect is it attacks your address book, mailing itself out - however it takes random people in your address book to both send TO and appear to be FROM.

My most recent annoyance with Klez said it was "from" Goatham. Basically someone who has both Goatham and me in their address book is infected.

Check yourselves. Remove this virus/worm.