Althea

Receptionist in the High-IQ Sperm Bank and later in the Emergency Room at the hospital where Leonard took Howard, first when he had an allergic reaction to peanuts (0116) and then a couple of years later when he, er, fell onto a robot arm (0401).

Althea appears as the receptionist in the unaired first pilot as well (0100).

Althea is played by Vernee Watson.

Wikipedia: http://en.wikipedia.org/wiki/Vernee_Watson-Johnson