How to easy obtain this achievement:

If you'd like to try to automate the process, here's what you do:
Start the game in windowed mode (800x600 best) and begin a tournament.
In settings, set the dialogue to minimum.
If you have not collected all of the game items from the other players, you may want to do so first. The script is not currently coded to handle them. After playing for an item, a dialogue box will appear that needs to be clicked away.
Install AutoHotkey http://www.autohotkey.com/
Save the following script to a file 'poker.ahk' on your desktop
______________________________________________________________________________
COPY ALL BELLOW::::


; This script will keep playing Poker Night at the Inventory

SetDefaultMouseSpeed,0
WinWaitActive Poker Night at the Inventory
Run()

; To stop the application at any time, simply press the Escape button
Escape::ExitApp

;Run the whole application indefinitely
Run() {
while true {
ClickCall()
SkipDialogue()
DealNewGame()
Sleep,500
}
}

ClickCall()
{
Click,182,520
}

SkipDialogue()
{
Click, right, 182, 520
}

DealNewGame()
{
Click,495,540
}

_____________________________________________________________________________
Double-click the 'poker.ahk' file to load the script, and switch back to the game. The script should start running automatically.
Hit 'escape' to exit the script at any time.

Leave the program running to continuously play poker and earn the Straight Flush achievement (or any of the others) while you watch, sleep or jogging...

Originaly posted and thanks to pokerdan99, i change script so that you can faster get this achievement.

and finaly....