I couldn't find it on the search, but I know it's been done at least one hundred times before. Whatever.
Subject is simple; take a video game that has no achievements and make some up for it, or make a ridiculous acheivement that doesn't exist for a game with an acheivement system.
Examples:
Mario Kart Wii:
Launch and Reentry: On Rainbow Road, perform a half pipe jump and fall off the track.
Take That, Losers: Racing as Wario, go from last place to first place and win the race, all in the course of twenty seconds or less.
Have a Rotten Day: As Wario, laugh at all of the other racers during the course of an online race.
This is Mario Kart, not F-Zero: In a Grand Prix or online race, knock another racer off the track by bumping into them.
One Small Slip, One Failed Leap: Hit another racer with a banana peel to prevent them from leaping off of a boost ramp.
Stalker on Speed: Obtain turbos by trailing other racers three times, each within ten seconds of another.
Snake? Snake! SNAAAAAAKKEE: Perform three drift mini-turbos in fifteen seconds. (This wouldn't be very hard in the DS version, but the Wii version uses time drifting instead of the D-pad thingy)
Jumpman: Avoid a POW Block's hit by jumping off a half pipe or a ramp.
Aerial Assualt: Hit another racer with a red or green shell within less than ten seconds of being shot out of a "cannon" and stopping (time starts as flight stops)
Flak Cannon: Hit another racer with a blue shell while they are in midair.
You Drive on the Left Lane in Japan: Be hit by ten cars while racing on Moonview Highway.
Alternate Route: Finish a race driving backwards. (I think you can drive backwards, I've never needed to.)
Row Row, Fight the Power: Maintain first place while being slowed down by terrain that slows you down.
Drive By: Driving the wrong way, blow up a racer with a Bob-Omb within three seconds of them passing you.
Rear-End Plan: In first place, when another racer passes you, hit them with a green shell within four seconds of them passing you.
Exploding From the Jaws of Victory: Win a race by blowing up the first place racer with a Bob-Omb, then winning the race within ten seconds of doing so.