I just saw this auction today - it is for 3 Harrah's Club calenders from 1955, 1956, 1957. What make it so interesting is that those are the dates when things were changing for Harrah's. On the 1955 calender the logo just says "Harrah's Club" - no city mentioned as he was only in Reno at the start of 1955. The 1956 calender has "Reno/Lake Tahoe" but it looks like it was added after the design was complete. The 1957 calender has "Reno and Lake Tahoe" and is clearly part of the design. I guess it was a bit later than that the logo was reduced to just "Harrah's" - he dropped the "Club".

Not my auction - no idea of the value...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120164214727