When I have trouble sleeping, I typically do one of two things. I find this time apt to clean the house [yes, in my pjs is when I think it's best to organize the spices in the kitchen cabinets or hang items from the ever-growing pile of clothes that accumulates in my room].
My other late night ritual is hunting for new music. My modus operandi involves sifting through the latest releases on itunes [with a focus on alternative music]. I basically sample 2-3 songs from each band, starting with the album's most popular song and then randomly choosing another couple tracks. If I absolutely love the few songs I listen to, I may buy an album or EP on the spot, but usually I'll just wish-list it until I've sorted through the majority of new music out there. I also like to peruse music review sites out there and this helps give me a well-rounded view of what's out there right now and what deserves another listen.
Give some of these a listen. Some are singles [with the hopes of fantastic albums to follow] while others come from albums worth buying in their entirety. My tastes is varied and changes depending on the day, my mood and for a whole other slew of reasons. That's what I love about it.