Maybe this will help:

http://www.contextures.com/xlDataVal02.html

Regards
Rowan

Warderbrad wrote:
the problem is not the lookup funtion, it is supplying the data for the
list in the Data Validation. Since the days do not have activities at
the same times I cannot use one list of values for everything. In the
example if a person wanted to attend on Sunday the drop down list would
have to have the options of 5-7 or 9-11, but if they chose Monday it
would need to have the option of 4-6. It is putting those values into
the data validation list that I am having problems with, not the
looking up of other values once the time and day are known.