If you still own a Nexus One and get annoyed for not receiving further software updates, then here is a good news for you.
A developer at XDA has successfully ported Android 4.4 on N1. Of course this is a first port so expect some bugs which are:

• Camera not working
• Bootloop(sometimes)
• No screenshot functionality

If you can compromise with these bugs, then this device perfectly fits as a daily  drives so without wasting any time, visit the source links below to download the ROM and rock KitKat on N1.

Source: XDA-Developers, (2)
Via: Engadget