2012!
Sunday.
It was a Thursday.
Wednesday
January the 1st 2011 was on a Saturday.
January 1st 2004 was a Thursday.
Saturday
Not always. For example: January 1st, 1962 was a Monday but January 1st of 2012 was a Sunday. For other part: January 1st, 1955 was a Saturday and January 1st, 2005 was a Saturday too. In general, your 50th birthday falls on the same day of the week of your birth or one day less.
August 1, 2012 was on a Wednesday.
Tuesday 1st January 1985.
January 1st, 2200 will fall on a Wednesday.
The 1st of January and the 1st of July are on the same day of the week in a leap year. So, at the time of this answer, that will next happen in 2016 and then again in 2020 and in all other leap years.