How to create a 'real' random value?

Probably overlooking something but I am struggling to get a random record that is actually changing each time. There is the option to get a random sample value, but this always gives me the same one, and same goes for generating a random value using the rand() function. Also here I get the same random number each time, while I want a new one instead.

I simply want to get a single random record out of a recordset, but it should be a different record each time I call the set. 

Any ideas?