April Fools Day seems like a good day for this list...they're not all "practical" jokes, some of these are just ways to mess with them.----------
Every April 1st send a birthday card to the Democratic Party.
Tell some really hunky member of PETA that he's a beefcake (you might have better luck hunting unicorn).
Accuse a liberal of plagiarizing Biden every time they burp.
Go the the Sierra Club office/treehouse and hang a sign outside the bathroom reminding the tree huggers of the Golden Rule, therefore toilet paper is hereby banned from use.
Attend a speech given by Rahm Emanuel, make that beeping censor noise every time he talks, except when he drops an F-bomb.
Convince people to register Democrat by promising membership involves lots of conveniently unspecific screwing.
Send PETA a cease and desist order from People for the Ethical Treatment of Real Ocean Life (PETROL) informing them the pens their offices use use ink extracted from squid.
Get the Koch brothers to sponsor a mailing of autographed pictures of Scott Walker to all Democrats, yes, all of them.
Petition the U.N. to make April 1st Global Warming Day.
Get 10 friends together to watch MSNBC at the same time to create a mysterious ratings spike.
Barge into a Planned Parenthood with a crying baby in your arms and demand your money back.
Go to any Democratic headquarters and announce that you are a registered Republican and your tired of the way President Obama has been treated and you're ready to show your support for him by re-registering to Kenyan.
Potentially start a Pakistani Muslim-esque riot by placing a personal ad on Craigslist in San Francisco titled "Looking For Love in all the Wrong Places" under the name G. Bush.
Distribute "special" brownies at demonstrations to legalize pot...neglect to mention they're special because they're made with Ex-lax.
Go into an uber-hipster coffee shop and throw a fit when they wont give you an off menu item, like coffee.
Ask every long haired hippie man you see for their autograph and that you love them on The View.
Photoshop years out of Nancy Pelosi's Wikipedia photo to make her look 70.
Brag to your liberal friends that you've decided to be friendlier to the environment by taking your bike everywhere you go, and then prove it by showing them how you keep it in the trunk of your car.
Do the magic trick where you pull a coin out of a Democrat's ear, but instead of a coin use a mini plastic brain.
Make them breathe a sigh of relief by telling them Helen Thomas is now registered Republican.
Get liberals to sign a petition forcing a Jeopardy showdown between the super-computer WATSON and TOTUS.
Barge into Planned Parenthood with a wire hanger and brag about how they taught you everything you know about choice.
Program the auto correct feature on their word processor to change words like "revolution" and "fair share" and "progressive," or anything else that sounds like liberal whining into "I <3 Reagan."
Change the nationality of every Democrat bio on Wikipedia to "Hell."
Make national news by starting a CNN fan club.