This year :) 2011
It will happen again in 2016, 2022, 2033, and 2039 and continue on a 5 year, 6 year, 11 year, 6 year pattern. It would be every seven years, but leap year causes this irregular pattern.
actually 2005 had 5 Fridays Saturdays and Sundays in July
Never.
Every year has more than 5 Fridays, 5 Saturdays and 5 Sundays.
Exactly 14% of all Decembers have five of each of Fridays, Saturdays and Sundays.
2011 2016 2022 2033 2039
Prior to this year, July had five Fridays and five Saturdays in 2010.
According to my desktop calendar, July will have five Fridays and Saturdays (and even some Thursdays) in 2016, 2021, 2022, 2027,2032, 2033, etc... If you look at http://www.timeanddate.com/calendar/monthly.html?year=2021&month=7&country=1 you will see that 2021, 2027, 2032 do not have 5 Sundays. The other years 2016, 2022, 2033 do have 5 Fridays, Saturdays, and Sundays. You are little confused since your first parahraph discusses Fridays and Saturdays, in which case 2021 and 2022 do indead have 5 Fridays and 5 Saturdays in July. In paragraph two above, you begin talking about Sundays and which years in which July will 5 each of Fridays, Saturdays and Sundays. Every month with 31 days will have 5 instances of the first 3 days in the month. This will repeat in a 5-6-5-11 year cycle and then repeat. So it should be 2016, 2022, 2033, 2039, 2044, 2050, 2056 - don't forget to consider leap year which will cause a 1 day shift.
March
It has 5 Fridays, 5 Saturdays and 5 Sundays.
This happens in any 31-day month starting on Friday (such as July 2005).
More like every 28 years, I think.
ummm...never.