I don't know what kind of environment you work at but some ideas I have are get up and walk around for 10 minutes or stand. Think about something that is interesting, I'm not sure what but I've stayed up past my bedtime focusing on interesting things. I also can't sleep when I'm angry about something so you could think about something that makes you angry.
I'm not sure if this is medically recommended but drink a lot of water or enough water where it feels like you have to go to restroom.
Also, my friend would blast the AC on long haul truck missions to keep himself awake but I'm not sure if you can touch the AC there or not.