I don't tend to write my tunes down in musical notation (I can't really read/write it that well anyway); I tend to write them down similar to guitar tabs, so taking the intro melody for Phoenix:
| C1 C2 Ab1 G F - C - | Eb - - - - - - - |
| C1 C2 Ab1 G F - C - | - Eb Eb F G F Eb C |
If you have a keyboard handy, just mess about on the keys until you get something.
(in case you're wondering, the numbers represent a change in octave)
Heck, I've gone through cold spells myself; I managed to come up with loads of tracks just by messing on the keyboard until something appeared.