These are what I am impressed by my son and thing that he may be gifted,
1. When my 2yrs old son asked me what is the English name of a 15-sides polygon, I checked it out and told him that it is called 'pentadecagon', then he shout happily: 'pentadecagon, hexadecagon, heptadecagon, octadecagon, nonadecagon' and i have to check it in wiki plus he is not a English speaker.
2. When my 2.5yrs old follow the step of LEGo menu designed for 7+
3. When my 2.5 yrs old write numbers in reverse order from 200, write odd and even number from 0-200, and keep writing for more than an hour.