TV guest stars who played more than one role

What guest stars on a TV show have appeared more than once, but in different roles?

Mark Lenard was on Star Trek both as Spock’s father and a Romulan Captain.

Albert Brooks has been in several Simpsons episodes, plus the movie.

Harry Morgan was a guest star on MASH (as General Steele), then returned to play Col. Potter as a regular.

Two similar threads of yore:

http://boards.straightdope.com/sdmb/showthread.php?t=540143 (if you consider early this week “yore”)

Janos Prohaska!! :smiley:

D’oh!