Soon it's the year $2016$. Time to ponder how we can arrange the digits in 2016 to form a valid equation. Use any symbols you like (please explain the less obvious ones). Keep digits in the same order (should this be relaxed?).
Examples:
$$\lfloor e^2\rfloor + 0 - 1! = 6$$ $$\left\lfloor\sqrt{\sqrt{201}}\right\rfloor = \lceil\sqrt{6}\rceil$$
where $\lfloor x\rfloor$ denotes the floor function and $\lceil x\rceil$ the ceiling.
Don't overuse constants (i.e. avoid adding up several $\pi$ and $e$ just to get to some arbitrary value).
EDIT: clarification: use each of the digits $2$, $0$, $1$, $6$ in this order only once. Combine digits giving $20$, $201$, $16$, etc as you like (I won't argue whether in a fraction the numerator or denominator comes first :-). Please don't criticize answers that violate this rule, as this clarification came late.
An easy one ;-) $$(2 + 0 + 1)! = 6$$