Face Memory Test
Skills like memory are the first to go when we're tired.
This test assesses your ability to remember how long ago something happened - your 'temporal' memory. If you're tired you won't be as good at remembering when you saw or did something.
The test is in three parts and we suggest you take a five minute break in between each part.
http://www.bbc.co.uk/science/humanbody/sleep/tmt/