Let's use Nick's 'problem', I've fallen asleep for a few hours, call it 3-4. So I could be in a 1,130,973 sq mile area. (150kts at 4 hours = 600nm radius) Which VOR or ADF am I tuning into? Shouldn't take me too long to go through the 200 VOR frequencies to try and get a match.
The only 'real' answer is call 121.5 and ask where you are. Of course, that's assuming that you are within reach of someone on 121.5 If the flight started on the east or west coast and you went east of west respectively, you might not be heard. Same goes for the middle of nowhere Canada, or Mexico, or...
Which VOR's are you tuning into again?