Try this one on for size
A man and his son were on a tour of an atomic power plant. In the control room, the boy asked if he could see the controls for the reactor core. The head physicist said yes, and explained how the controls worked. After the boy left, the head physicist turned to an assistant and said, “That was my son.”
How could that be?
Are you serious?
Obviously, the head physician was the boys father.
Although it is quite late, and my mind may be elsewhere…
Ive got one: 
You are stuck in an air tight room. You only have 15 minutes worth of oxygen left. There are no windows, there are only two doors. And in this room there are 2 computers, one is programed to tell nothing but the truth. The other is programed to tell nothin but lies. You can ask ONE question to ONE of the computers. If you touch the wrong door both of them disappear and your stuck.
What do you ask and to which computer to get out? 
~ceavou~
Hey, I already told this riddle gg
Here is a short one for you mathematicans:
A snail fell down a hole.It is 30cm deep, and the snail trys to escape as fast as possible.It goes up 13cm every day, but the following night it always has to sleep (and dream g) and slides down 7cm.
How many days does it take the snail to get out?
Traumgänger
for the man and son… the son could be a new employee and the father was showing him the ropes
for the other one… you ask either of the computers “which door would the other computer tell me to go in.” and then go in the opposite door.
For the one with the snail and the hole… 4 days 
the anwser to Jestas riddle is that the head physicist is the boys mother
I like sleeper’s answer better 
Here is one (more math):
A 12x30 foot room has a 12 foot ceiling. In the middle of the end wall, a foot above the floor, is a spider. The spider wants to capture a fly in the middle of the opposite wall, one foot below the ceiling. Considering that the spider must always be crawling along the wall, what is the shortest path the spider can take?
Also:
There are three boxes labeled “Apples”, “Oranges” and “Apples and Oranges”. Each label is incorrect. You can select one fruit from one box, and you can’t feel around or peek. How can you label each box correctly?
Both of these aren’t very hard. The first one is a little bit strange. The answer is not 42 for the first one.
Sorry traumgänger 
I just joined this thread and it was obviously a bit late. 
~ceavou~
I agree the answer to Jestas riddle is certainly that the head physician is the boys mother. However, it never states that the man walking around with his son is not the head physician.
Perhaps if it said that the man on tour with his son did not work there or something… 
Anyway, here’s mine.
Add punctuation to the following phrase to make something gramatically and logically coherent:
“i had had had tom had had had had had had had had the praise of the teacher”
Don’t ask me for the solution, I have absolutely no idea
kmcdonald 33.10589, is this how far the thing has to walk. (i remembered that the quickest way is a straight line!)
And for the other one, you put your hand in the one marked ‘apples and oranges’ if it is apples then you put the ‘apples’ sticker on it, or ‘oranges’ sticker if there are oranges. If it was apples then you put the ‘oranges’ sticker on the original apples box and the ‘apples and oranges’ on the original ‘oranges’ box.
eg,
‘apples’ ‘oranges’ ‘apples and oranges’
if there are apples, label it like this:
‘oranges’ ‘apples and oranges’ ‘apples’
for the spider on the wall riddle I got 40 is this right ?
40 is the shortest distance I am aware of. If you could explain your answer, I would be grateful alex.
now playing in a theatre near you: Riddles part II - the chaos continues…
https://community.ld4all.com/t/riddles-part-ii-the-chaos-continues/5731