Nerdball: Did You Hear What Happened In Math Class?
ILOVEMATH: Erm, No? What? Tell Me
Nerdball: The Final Exam Was Changed To Friday
ILOVEMATH: *GASP* Are You Serious? I Studied For Hours!
Nerdball: Psych!!
ILOVEMATH: Don't Scare Me Like That!
A TV show about a guy named Shawn who fakes being a psychic (he has a near perfect memory) to avoid going to jail and ends up working as the Santa Barbara police station psychic.
Shawn: Good morning, detectives. Collecting Money for the Policeman's ball?
Lassie: We don't have balls.
Shawn: ... I honestly don't have a response to that.
Shawn: Remember, Dad. Treat a woman like a person, then a princess, then a goddess, then a person again.
Often believed, by those who don't understand the term's origin, to be spelt (or spelled, for the American audience) 'sike'.
Deriving from the word psychology, psych is a term used to indicate that whatever the person speaking just said was done so purely to mess with the listener's mind, to 'psych' them out, if you will.