My Motorola Droid and Nexus One are prone to mysterious crashes and lockups. They have both been that way since day one and through various firmware updates. The Droid is currently at 2.1 while the Nexus One is at 2.2 (Froyo).
The Nexus One provided one of the worst experiences I’ve seen on an Android phone so far. It crashed during an incoming call and completely locked up. You can see what this looked like in the photo above. None of the screen or hardware buttons worked after this point. I ended up removing the battery and then reinserting it to restart the phone.
Not only was I unable to answer the voice call, but the call was not logged at all. I saw the incoming phone number. It was not something in my contacts list. So, I’m pretty sure it was a “wrong number”. However, I am quite annoyed by this experience and the generally flakiness I’ve seen in both of my Android phones since buying them.