I came across this brainteaser on another forum and am submitting it here if you have nothing better to do for a few minutes :-)
Instructions are as follows:
1. Click on START
2. There will be a countdown: 3, 2, 1
3. A series of single digit numbers will appear.
4. The numbers will be replaced by blank circles.
5. Click on the blank circles in numerical order, low to high.
6. At the end you will be assigned a Brain Age
7. Post your real age & "brain age" - and be honest about both!!

I'm 57 and my brain age was 35.

Mike