What was the day of the week on 28^th May, 2006?

Sunday

28 may 2006 = (2005 yrs + period from 1/1/2006 to 28/5/2006)

odd days in 1600yrs = 0

odd days in 400yrs = 0

5yrs = (4 ordinary yrs + 1 leap yr) 

=> (4 x 1 + 1 x 2) 6 odd days

jan 31 + feb 28 + mar 31 + april 30 + may 28 = 148days

148 days = (21 weeks + 1day) = 1 odd day.

total no. of odd days = (0 + 0 + 6 + 1) = 07 

Thus, the 28th may 2006 is Sunday.