Does looking at the flames of candles or lighters or watching ceiling fans spin calm you down at all by chance?
Failing that, how about relecting light onto your wall using a pocket mirror and playing with it, just experimenting with the reflection?
If that doesn't work, find the 214861th number in the following series:
5, 11, 17...
Fill in the missing numbers:
1, 7, _, 37, 61, 91, _, _, _, ...
Or perhaps you could envision a fictional world in your head, write it down, and start describing it? Try imagining interesting things perhaps?