April Fools' day is upon us, so it's only right to share a few harmless programs you can use to make things more interesting around the office tomorrow. Remember to check your usage policy and bring a pair of latex gloves so you're not leaving fingerprints at the scene.

Don't forget to swap the M and N keys on someone's keyboard. It's subtle, annoying, and timeless.

Fun with Short URLs
With so many people sharing so many links on Twitter, the most obvious prank (and easiest to pull off) is a Rickroll or some variation. Tweet something intellectual sounding - heck, post it as an RT of something else and insert a short URL that points to something immensely annoying like any one of the YTMND Hobo Cruise videos (pictured above).

Set a coworker's wallpaper to an animated GIF
Again, YTMND clips are an excellent choice. Set an obnoxious animated GIF as your pal's wallpaper - tiled, of course. It's not only an assault on the eyes, but on the CPU as well - you may well bring their system to its knees, or at least make it painfully sluggish to change their wallpaper back to something more business-like.

Schedule all manner of mayhem with nircmd
Nir Sofer makes a ton of really, really useful applications. Seriously. He probably never intended them to be used as juvenile pranks, but nircmd just lends itself so well to harmless hooliganism. Schedule a task to open and close the CD tray, randomly turn the system volume all the way down and then crank it up full blast moments later, kill all IE process, display the start button on the system tray - the list goes on and on.

This one is pure gold, and it's actually quite handy the other 364 days of the year as well.

My primary phone is a BlackBerry, but I also own an iPhone with no service contract. Several weeks ago I had the lucky gig of compiling a few fart apps for TUAW, and I was less than impressed with the overall situation. In other words: most fart apps stink.

But let's face it, fart apps made a lot of noise for the iPhone, in no small part because Apple initially refused to "pull the finger," effectively blocking them from the App Store. Now the fart app floodgates are open, and the App Store is flush with flatulence. It was only a matter of time before other platforms took the bait and improved upon the iPhone apps in ways the iPhone simply won't allow. Sort of.

You can see a long, boring, detailed breakdown of features for BSFartApp ($1.99) by clicking the read more link, but here's the basic deal: BSFartApp is a complicated and powerful fart app for Windows Mobile. I have nothing against novelty apps. In fact, BSFartApp is superior to many iPhone fart apps in features, but it really falls down in terms of actual usability. Maybe WinMo users are conditioned to doing things in 3 clicks instead of one, but I am not.

As one example of terrible UI, in order to navigate down a menu, you must click AND swipe. Do what now? Why not just swipe? Or just click? The buttons have little arrows that would seem to indicate such functionality, so why not do as the user expects? Also, while there are plenty of use cases for timed or triggered farts (yes, the office clown, we love him, but will he make it to the corner office?), what about just letting one rip? Yeah, you're gonna be about 3 or 4 menus down to just let one go. Thank goodness our own bodily functions are less complicated. Things are bad when you start referring to generic soundboard apps on the iPhone as "elegant by comparison."

BSFartApp's real advantage over iPhone is the ability to send a fart via MMS. Plus, there's a pretty nifty "eavesdrop" feature that should have you getting sued and/or grounded in no time (there's a similar feature that returns the GPS coordinates for supported phones). I'm less impressed with the phone-as-web-server, since the iPhone will do that as well, but WinMo still has an advantage by allowing background processes to run. OK, so I guess it's good that WinMo is getting a little fart app action. Now if only it wasn't such a PITA to use them...

You knew your Mac could detect wireless networks and Bluetooth devices, but did you know it can also detect spirits? If you want to scan for supernatural activity, download an app called EMF6742, from the Department of the Supernatural. This little program uses your Mac's wireless hardware to scan for anomalies in electromagnetic fields, indicating nearby spirits. A higher number means a stronger anomaly in the EMF.

System requirements include "Mac OS X 10.5 or later, a wide variety of superstitions and/or a sense of humor." Yes, unfortunately, EMF6742 is just a joke. Apparently, some people downloaded it without realizing this, though, so if you're looking for something to show your friends to put the "trick" in trick-or-treat, give it a look!

On the plus side for Muxtape, the service has only gotten better since its initial launch. It's now playable from iPhones, and plenty of sites have popped up to catalog the best and most interesting Muxtapes. The site is down right now, presumably being fixed, and we will update this post as we get more information on the battle between Muxtape and Babybird's Prince thing. Is this a publicity stunt by the band, or just a prank?

UPDATE: Muxtape is now saying that this may have been a result of a database problem and not any kind of breakin, but the cause is still undetermined. The site should be back up by tomorrow, and everyone's mixes were probably backed up and should be restored.

Naturally there's a paid version you can upgrade to, but the free one, MorphVOX Junior is pretty fun itself. It's a voice changer application for Windows from Screaming Bee. No, you can't change your voice to a screaming bee, whatever that would sound like. Your choices are Tiny man (like helium), Man, or Woman. While this app is free of spyware and such, it does run little banner ads at the top of the application itself. Not a bad price to pay for a fun little gizmo like this...