You can use ASTRO to backup an app or game from your phone to your SD Card, then
insert the SD card into your GF's phone and install the app or game onto her phone.
Details:
Open ASTRO on your phone.
Hit the menu button and choose "Tools".
Choose "Application Manager/Backup".
You then get a list of apps and games that are installed onto your phone.
Next you want to select the games you want to backup.
Then hit the button "backup".
You can then close ASTRO, turn off your phone and take out the SD Card.
Insert the SD Card into your GF's phone.
Open ASTRO and navigate to the folder "backups" -> "apps".
Open the file and install
Hope this helps you a bit more