Are you guys wiping off the screen? Greasy residue from your face can block the sensor...or at least so I've read on these forums in the past
I've had this problem as well. I installed "sensor test" and it seems to have fixed the problem? I'm using Screebl and Advanced Task Killer and after downloading that program the screen has begun to work correctly after calls.
I've had the same problem randomly. The last time it happened I was using speakerphone and screen went black after about ten minutes. Sometimes when ending calls I have to wait for the other person to hang up because nothing makes the screen light up.
My original launch Droid did this and caused me to have to do a battery pull whenever the screen wouldn't come back on at the end of a call. The entire phone was on, screen lit, but would not react to any button, including long or short presses on the sleep button. During the course of a week it had done it about eight times, totally unacceptable. Luckily I was within my 30 day return so I swapped it out.
Good as new. The new Droid I have here is perfect and lights up perfect every time for the past three months since replacing it.
There are phones out there with genuine faulty proximity sensors and if yours does this, ignore the suggestions about facial oil blockage or screen protectors or even downloading apps to fix it - it's all bunk excuses. Get a replacement ASAP. There is absolutely no reason for this to be happening.
Do the sensor test. I got a refurb this week that had a faulty sensor and would go black as soon as I dialed and would not wake up without sliding open...and sometimes required a battery pull.
Just got my refurb phone cause the first one (bought on day one 11/5/09) died. The refurb screen goes black as soon as the call is connected and won't come back unless I slide it open or pull battery. I called Verizon tech support and they're sending another refurb to me. Oh joy another one of these POSs!
My phone had this problem, then I decided to peel off the screen protector. The screen protector blocks this sensor... When it was on, it would go blank and I had to hit the power button to access the dialpad. I took it off, it works properly. I have a mirrored screen protector, maybe the transparent one won't do this. For now, I have replaced the protector, but plan to replace it with a clear one.