It was planned for May, but then the then-impending liftoff of STS-114 intruded on the launch date, so it was moved to the fall. Then after the launch in July, preparation for the next flight (that will not have launched until well after the 2006 chili cookoff) pushed the 2005 cookoff far enough into the year that there was no room at the Gilruth Center any more. So there was no cookoff.
Oh, there are some who will say that a traveling cookoff in the Hill Country took its place this year, but nothing will fill the empty void left in the souls of those participants who wait in vain, yearning for the next cookoff. Well, OK, a beer will do fine, but still.
See you in 2006!