Have anyone played Yahtzee game?

It's a popular game with 5 dice and you can roll up to 3 times: http://boardgamegeek.com/boardgame/2243/yahtzee

My question relate to this game. Assume that you have 5 dice, in turn you can roll, keep and re-roll any dice up to 3 times.

What is probability in

**3 times roll**to get:

Specific "2 of a kind": 1-1, 2-2, 3-3, 4-4, 5-5, 6-6.

Specific "3 of a kind":1-1-1, 2-2-2, 3-3-3, 4-4-4, 5-5-5, 6-6-6.

Specific "4 of a kind":1-1-1-1, 2-2-2-2, 3-3-3-3, 4-4-4-4, 5-5-5-5, 6-6-6-6.

Specific "3 in a row": 1-2-3, 2-3-4, 3-4-5, 4-5-6.

Specific "4 in a row":1-2-3-4, 2-3-4-5, 3-4-5-6.

Specific "5 in a row":1-2-3-4-5, 2-3-4-5-6.

Total above or equal 15.

Total above or equal 20.

Total above or equal 25.

Any two different pairs (ex,2-2 and 3-3).

Any full house (ex, 2-2-2-3-3).

Any three of a kind (ex, 4-4-4).

Any four of a kind (ex, 5-5-5-5).

Any small straight (ex, 1-2-3-4).

Any large Straight (ex, 1-2-3-4-5).

Thank you,