My favourite way of trying to get back to sleep in the middle of the night, once I've taken a Kalms and doused myself with lavender oil, is to think up alphabetical lists. I've listed world cities, countries, foods, flowers, birds, animals, surnames - anything I can think of! I sometimes try to find more than one thing per letter and when I was doing "composers", I found 10 for the letter B. (Don't worry, I'm not going to list them all here!) I know this works quite well because I often don't get to the end of a list, as I've fallen asleep!
Also, sometimes I try to make up limericks (with the emphasis on "try"!), which I don't usually remember, except for this one:
A violinist called Locatelli
Was very good friends with Corelli.
They did a recital
Which proved to be vital
'Cos then they were picked for the telly.
(They'd been talking about these people on Radio 3 when I was driving home earlier, not that the bit about the telly could have been right, as it hadn't been invented then.........!)