April first is right around the corner, which means you need to put all other thoughts aside and ask yourself: "How can I, as a cyclist, make a fool of my friends and family?"
Due to the expensive nature of the sport, the complex social interactions involved, and the obscene amount of time cycling requires, your April Fools' jokes options are practically unlimited.
I offer these as examples.
If you are anything at all like me, you have from time to time tried to sneak a bike into the stable, hoping your better half won't notice one more bike among the legions already there. Therefore, if your significant other is anything like mine, she (or he) makes a point of scanning the garage on a daily basis, taking inventory of your bike stable to see if it has grown.
So, this April Fools, borrow a bike -- a really nice bike, of about the same size of your other bikes -- from a friend. Not to ride, but just to park. Put it by your other bikes in such a way that it looks like you're trying to hide it.
And then don't say a word.
When your spouse/boyfriend/girlfriend/whatever eventually notices and asks about the bike, simply reply, "It's just a bike."
"You bought a bike without consulting me?" will be the response.
Look away. Swallow. Stammer. Then say, "Not exactly."
"Exactly what, then?"
Which is when you say "April Fools!" and you both have a good laugh, or you get clobbered with the nearest heavy, blunt object. Could go either way.
Let the Air Out of One Tire
Before the ride, let all the air out of one of your riding buddy's tires (while they're not looking, of course). It's a well-known fact that cyclists have a conditioned reflex to flats: go into FFTT (Flat Fix Time Trial) mode -- see how fast they can fix the flat, without ever taking into consideration the possibility that nothing at all is wrong with the tire, except of course that there's no air in it.
The best part of this trick is, of course, watching them futilely hunt for the offending thorn or piece of glass in the tire. Just for fun, keep count to yourself of how many revolutions of tire inspection they go through before giving up.
Bonus money-saving trick: After your riding friend has changed the tire, volunteer graciously to take the tube. You'll get points for taking a bad tube off their hands, with the added benefit of having been given -- absolutely free -- a perfectly good tube.
This one requires some coordination between several of you on a group road ride. Together, all of you (except the guy you're playing the trick on) make up a new hand signal, which you will mix in with your usual callouts of road debris and obstacles.
For the signal, I recommend pointing down to the ground with all fingers splayed, then bringing them in close. Repeat three times.
Then, at completely random moments, use that signal. When you are asked what it means, roll your eyes and laugh as if you'd heard a good joke.
Make the Call
Call your significant other from your mobile phone during the middle of the ride. Instead of beginning by saying "Hello" or "Hey, it's me, how's it going," open by saying, "First, I want you to know that I'm OK."
This will have the exact opposite effect on your significant other, causing them to think that you have in fact been run over by a train.
After letting their mind wander for a moment, ask what's for dinner. Play innocent when they express outrage. "What? Why would you think I've been in an accident? That's ridiculous."
Call a riding buddy and cancel an agreed-upon ride. Say "I'm reevaluating my priorities and realize I need to spend more time with the people in my life that matter. Riding isn't the most important thing in the world."
At this point, of course, your buddy will call you out. This April Fools joke simply stretches credulity beyond the breaking point.