This list is inspired by many others on the Internet, as well as some dearest lecturers in NUS.
Always a WIP, so feel free to add on to it!

Proof by amnesia. Forget everything. Life is too short.

Proof by best effort. Try your damnest to prove something. After a sufficiently long process, write "I've tried my best => Q.E.D."

Proof by blatant assertion. Do lots of things "by inspection'', use the phrase "It is blatantly obvious that...''.

Proof by boredom invocation. Assume the personality and teaching style of a mouse. Make everyone lose their interest and the fight against sleep.

Proof by bovine excretion. Mix three or more proofs stated here.

Proof by coercion. Tell your students that every proof you demonstrate correctly will not be examinable. Watch them nod sagely even when you say 1+1 = 10000.

Proof by CIA. Say that its true because top level agents supplied you with intelligence, even if that intelligence happens to be a pile of dung.

Proof by concensus. If all your friends agree with it, then it's true.

Proof by convection. Use lots of hot air and hand waving. Works impressively in a large room.

Proof by conversion. If you get x = 4 and you need x = 100, simply convert the proof to binary. Works well for all other bases.

Proof by delegation. "This proof is left as an exercise."

Proof by denial. "I can't proof it, ergo the proof does not exist, ergo this theorem is wrong."

Proof by divine intervention. Somewhere in the middle of your proof a miracle occurs.

Proof by elimination. Drop the terms that are hindering you.

Proof by emergency. Whip out your lighter and set off the fire alarm. In the ensuing chaos, pretend you've finished the proof.

Proof by exasperation. If you stare at a partial, incorrect proof long enough, it slowly looks more and more like a complete, correct proof.

Proof by extrapolation. "1+1=2 ergo n*m = nm ergo Men are from mars ergo Tutte's theorem is true therefore Q.E.D."

Proof by hilarity. Tell a joke midway in the middle of your proof. After wiping tears from your eyes, follow up with Proof by amnesia by saying "Now moving on to our next objective of the day..."

Proof by HTTP. It's on the Internet hence it must be true.

Proof by hypnotism. Begin proof with "You are growing verrrry sleepy..."

Proof by illegibility. If no one can read it, how can it be wrong?

Proof by inebriation. Every time you write an equal sign, take a shot of beer. By the time you're done, the proof makes sense to you even if nobody else gets it.

Proof by interpolation. If you do two proofs and get two different answers and the answer that you want lies in between, just take the average.

Proof by intimidation. Write down something which is obviously wrong, then fiercely tell the students that those who don't agree will fail the course.

Proof by intuition. If it feels even remotely correct, then it must be.

Proof by litigation. Sue the student who challenges you (slander could work). You may not win the suit but you'll bankrupt the kid, thereby silencing all other students.

Proof by maximal economy. Use the easiest and shortest way to proof a theorem. Masters of this method find it easy to write one-line proofs (eg, => Q.E.D) . Detractors call it Proof by least effort.

Proof by misconception. "2 equals 3 for large values of 2." Once introduced, any conclusion is reachable.

Proof by mutual reference. "In reference A, Theorem 5 is said to follow from Theorem 3 in reference B, which is shown from Corollary 6.2 in reference C, which is an easy consequence of Theorem 5 in reference A."

Proof by obfuscation. Generously apply Greek letters, sequences, series, partial derivatives, complex numbers, lemmas. Distance your solution from the original problem as much as possible. Once your audience looks sufficiently perplexed, cancel everything, write => Q.E.D.'', and smile confidently.

Proof by observation of simplicity. Despite its complicated name, this method is easy to use and highly popular. To successfully quell the majority of dissenters, just liberally pepper your proof with the phrase "the next step is really simple actually". Also called Proof by invoking fear of appearing stupid.

Proof by parentheses-insertion. If you have 3 + 14 + 1 = 20 notice that adding parentheses will solve the problem: (3 + 1)(4+1) = 20

Proof by posturing. Prominently hang your various degrees around your neck while presenting your proof.

Proof by prediction. Write down what you want to prove, then predict that one day it will be proven. Whip out some Tarot cards to support your claim.

Proof by ridicule. When challenged, arrogantly call the person an egghead and go all out to tear his reputation into shreds.

Proof by redirection. Explain to your students that it's not really your area of focus. Encourage them to seek help on the forums.

Proof by religion. Describe your proof, tell your students they have to take it on faith.

Proof by religious opposition. "This theorem is against my religious principals."

Proof by reduction. At each step, ignore some detail of the original problem. Continue the reduction process until the original problem has been reduced to something trivial, at which point the proof is complete. BigO analysis is a classic example of proof by reduction, except you can just
drop all the terms and write O(0). Recommended for CS1102/ CS2104/ CS3215 students.

Proof by saturation/ exhaustion. Compile a 10-page proof on 1+1=2, and another one on why 2+2=4 and so on. Use those as lemmas in your proof so that its 6000 pages long.

Proof by seduction. "Whoever believes me gets an A+ for this module".

Proof by semantic shift. Change standard but inconvenient definitions for the statement of the result. Also called Proof by re-definition.

Proof by shock-and-awe. Present your complex, and wrong, proof in a frenzy, ensuring that no one catches it. This is the awe part. The shock part comes when you scream obscenities at the top of your lungs at that idiot who asks you to slow down.

Proof by suppression. Get security guards to sit in the LT, with instructions to remove students who speak. Proceed to ask for opinions after presenting a ridiculous proof.

Proof by transitivity. The power of this proof method is awesome, as demonstrated by the ridiculously logical example "Logic is better than nothing. Nothing is better than sex. Therefore, logic is better than sex."

Proof by truncation/timeout. Cleverly leave your proof until the end of class. When time is up and you have not yet finished the proof, announce "We'll continue this proof next class'' and then promptly forget about it. If ever reminded/ questioned in future lessons, revert to Proof by delegation.

Proof by wardrobe malfunction. Expose your mammaries for all to see and drive out all thoughts of boring proofs. Also called Proof by Janet.

Proof by wishful citation. Cite the negation, converse, or generalization of a theorem from literature to support your proof.