StudyFail

Collegehumor.com got this first, but hey, here it is:

Study = no fail
No study = fail

Study + No Study = Fail + No Fail
(No + 1) Study = (No + 1) Fail

Study = Fail

Okay, let's take a look at the math behind that. I'll assume the following values.
Study = 1
No = -1
Fail = -1

Ergo
1 = -1 * -1
-1 * 1 = -1

So far so good.

1 + (-1*1) = -1 + (-1*-1)
(-1+1)*1=(-1+1)*-1
1=-1

Turns out the wiseguy just did the old "divide by zero" trick made famous by the following riddle:
x=y
therefore 2x=2y
x-y=2x-2y (because they're both zero)
1(x-y)=2(x-y)
1=2