Rarely do I get into one of the situations you describe, but when I do, I'll admit it is horrendous. The things I would try are:

1. Eating something
2. Turning on talk radio
3. Just tell myself, if I can't sleep, I will just lay here with my eyes shut and get as much rest as I can that way. Generally I do drift off eventually. Once I start this process, I do not look at the clock.