I have the exact same issue!
I enjoy watching repeats of TV shows I used to enjoy when younger. Same with reading.
Other than that try and change the way you think about your day. For example In a 'normal' routine someone might do work all day, eat and then relax, TV or anything leisure only after say 7pm, before sleep maybe 10-11pm.
Which is fine, if you then get up somewhere between 7-9am.
But if your like me and sleep somewhere like 4am - 12noon (or later I have been over Christmas!) then by the time you are out of bed, dressed, and eaten etc you don't have much time before the 'don't work after this time' of 7pm. I was finding I got so little done, and had so much free time I'm not sure what to do with.
So, if when in the 'wrong' sleeping pattern change all the times to be 'wrong' to match. So you get the same amount of work or active time as you should, then the same amount of relax or leisure time too. Even better it then seems to help you sleep because you've been busier in the 'day'.
I hope I explained this so you understand, if your unsure what I mean please ask.