This year, WestJet chose April 1st to proudly announce WestJetX, its new affordable orbital passenger service, on Twitter™:  "Taking payloads without making you pay loads."
It's quite elaborate and fairly clever, featuring videos and stills with quite high production values featuring space planes, floating pretzels, and a convincing looking spacesuit, along with some well-written copy regarding pressurized cabins ("for breathability and comfort") and the option of one-way tickets to "cut the cost of spaceflight in half".  
However, I can't quite give it full points as an April Fools event, because it ultimately just becomes a commercial for WestJet, albeit a somewhat tongue-in-cheek one.
By comparison, Ian McCollum's video review of Fallout 3 weaponry has 
that perfect combination of absolute seriousness and complete randomness
 that makes for a good April Fools gag.
McCollum, aka "Gun Jesus", is
 a gun collector, researcher, author, and the genial host of Forgotten 
Weapons, a YouTube™ channel where he knowledgeably discusses rare and 
unusual firearms as well as historically significant weapons.  This odd 
niche has been ridiculously successful, accumulating almost 2.5 millions 
followers on YouTube.
For April 1st, Forgotten Weapons took its usual
 detailed look at the Type 93 Chinese Assault Rifle, familiar to anyone 
who served in the campaign against the Chinese invasion of Alaska and 
Operation Anchorage, which freed Alaska's capital from Chinese 
occupation.
I'm just a little disappointed that he didn't feature 
something more exotic  like the Fallout 4 plasma pistol
 or the M42 "Fat Man" mini-nuke catapult launcher, but I can see how choosing the Type 
93, which is in the style of a conventional automatic weapon, makes it 
less obvious that it's a joke. The casual viewer might not notice at 
all, although the additional of radiation signage in the background is 
probably a strong hint. 
 
 
I have to give Mr. McCollum full points for 
earnestly delivering the same degree of scholarly historical detail and 
in-depth analysis for the Type 93 that he provides for any of the 
weaponry that he profiles on his channel.  He glibly explains how the 
Type 93 probably first sees production during the mid 2020s, looks at 
modifications for enhanced hand to hand combat due to reduced ammunition
 availability during the Resource Wars of the 2050s, 60s, and 70s that 
precede the global thermonuclear exchange between the US and the PRC, 
and even discusses the different versions of the Type 93 that are 
chambered for 7.62x39mm, for domestic Chinese use, and the 5.56 version 
covertly smuggled into the United States as part of the planned Chinese 
infiltration of the Washington DC area.*

The most surprising part of the video is that the sample weapon appears 
to be a fully functional rifle (supplied to Ian by Elder Alex of the 
Brotherhood of Steel) to the point that Ian is able to break the weapon 
down and apparently try it out on the shooting range.  Wow - now I 
REALLY want to see him do a feature on the mini-nuke launcher.
- Sid 
* And the resulting need to modify the original curved magazine to 
accommodate the straight-walled 5.56 cartridge as opposed to the tapered 
7.62 - it really is impressively detailed. 
