You can find a live image in gnome's website:
Getting GNOME | GNOME
Try the latest release
GNOME 3.12 is the latest version and will be available in distributions in the future. In the mean time, you can try our live demo image.
Instructions for installing the image on to a USB stick with GNU/Linux:
- Insert the drive (any data it contains will be erased!)
- Run dmesg in a terminal: this will give you the location of the stick in square brackets, such as sdb
- To write the image, run sudo dd if=gnome-3.12.iso of=/dev/DRIVE bs=8M conv=fsync, replacing DRIVE with the location (e.g., /dev/sdb but not e.g., /dev/sdb1)
- Once the write operation has finished, you can reboot with the USB drive inserted (you may have to specify the boot device on startup)