I had this weird idea today so I thought I'd give it a try. Wikipedia has listings for all the #1 singles in the top 100 of ever year so I thought I'd go through and see if I could post the ones for every year from 1940 up to now, sans repeats.
1940 only had three number ones so here they are.
July 27th - October 12th
October 19th to December 14th
December 21st - December 28th (Going all the way to March 8th of 1941!)
I hope you guys find this interesting, 1941 has a whole bunch so stay tuned!
Edit: I decided a whole new blog would be the way to go for this, so go here and comment: http://billboardnumberones.blogspot.com/2010/01/1940.html