Can't wait for a taste of Gingerbread (Android 2.3) on your Nexus One? Nexus One will more than likely be first to receive the update, but if you really can't wait, thanks to Chris Soyers you can manually install Gingerbread to your Nexus One.
Please take heed to the following, this is a working version, and yes, there will be bugs. There are no Google Apps available, or gapps as we call them in the Android community. This is a no frills version of Gingerbread with missing Google luxuries, such as Android Market access. Many apps may not work, like your camera, as you will see in the YouTube video below.
Follow the instructions:
1. Download the Gingerbread build from Mr. Soyers. (link) Copy it to your Nexus One's SD card.
2. (If you have custom recovery already, skip to no. 5) If you're running a stock Nexus One, you'll need a custom recovery to flash the Gingerbread build. Easiest thing to do is to download Amon Ra's recovery (link), then copy it to the /tools folder in your Android SDK directory. (You've already downloaded that, right?)
3. Reboot the phone into the bootloader (turn off, hold trackball and power) and plug into your computer. Make sure your hboot verison is 35.0017. (If you have the latest OTA, you should be good. But double-check.)
4. Type fastboot flash recovery xxxxxxxxxxxx (where xxxxxxxx is the exact filename of the recovery image, including extension).
5. Now enter the recovery (from choose "bootloader," then "recovery").
6. Wipe data and cache (always a good practice)
7. Flash gingerbread_passion.ctso.zip
Gingerbread on the Nexus One