Quote Originally Posted by audioinjection
this happens to me all to often

I usually find just sitting down and messing around with sounds even though i have no ideas, and just putting something together until it sounds good....then i would take a break and go back, just think of the song and what u can do with it
Something along these lines that you can do (and unfortunately its easier with hardware) is to just get some sounds going and sequence those sounds alone. Tweak the crap out of them, morph them, get bored, get another sound/melody going or maybe just some synthesized drums, patch your gear in different ways etc, just experiment and have fun (the ideas will flow and bounce off each other).

While you're playing around you should be recording it so you can use it later by chopping out the good bits. Keep to the same tempo and label it properly when saving (and include the tempo in the filename)

At the end of your session you should have a whole bunch of ideas already recorded and ready for working into tracks (or adding to tracks that needed that something extra)