List of Mario Kart DS glitches
This is a list of glitches in the game Mario Kart DS.
NOTE: Unless otherwise noted, all names are conjectural.
Delfino Square Boardwalk Glitch
When the player goes up to the boardwalk that has the one Item Box, they must press when they are on the wall. If timed correctly, the player can float on the side of the road. This will work in any mode.
Dropping off the Track Without stopping out of Bounds
In Cheep Cheep Beach, at the double-stone arch, the player must be touching the stone arch while holding right on the until the player drops. If done, the player will be in the "Out of bounds" zone but not stopping out of bounds. The glitch will end if the player presses or , or if the player stops touching the wall. Lakitu will return the player to the track as normal.
Go through an Invisible Barrier
In GCN Luigi Circuit, the player needs to turn around when the race starts and use a Mushroom on the corner of the bump and hop. If it was done correctly, the player will go through the invisible barrier and fall through the hills and the character will not make a sound. The screen will just blackout and Lakitu will bring the player to the track.
This can also be done in Bowser Castle, by going past the room with the Thwomps and then the player should see two "hills" with a spike fence. The player needs to go to the first "hill" and use a Mushroom and hop. The player will fly past the fence and go through the bar and fall into the lava. These glitches are best done with the Egg 1.
Goomboss Jumping Glitch
This glitch is difficult to perform and sporadically occurs. When playing mission 3-Boss, if the player can manage to hop into Goomboss as he is right near the edge of the median, Goomboss will jump over it as he does on the third lap. The player must do this while Goomboss is close to one of the turns though. This glitch can either help or hinder the player depending on where it occurs.
High Flying in Rainbow Road
In Rainbow Road, when getting to a loop, the racer should hit the fence and push while holding down on the . After a little while, the player will start to fly away and Lakitu will pick the player up and put him or her on the beginning of the loop. This works best on the corkscrew.
Luigi's Mansion Freeze Glitch
To perform this glitch, the player must pick the Luigi's Mansion track in any mode with any character and kart. Once the race starts, the player must then park their character on the stairs at the entrance of the mansion. After that, hold down both and to drift in place. If the player tries to turn, the game will sometimes freeze. This glitch was fixed on the Wii U Virtual Console release. This freeze glitch can also happen on multiplayer mode. If one player does the glitch and if the other player isn't at the scene, they'll be granted with a communication error. However, if the other player is there to watch the glitch happen, both players' games will freeze. 
Waluigi has No Voice
In Battle mode, if the player is Waluigi, for unknown reasons, his voice will occasionally disappear. This will last until the player quits Battle mode.
Permanent Rocket Boost
After the player gets a perfect Rocket Start, the player should start snaking. If done correctly, the player could drive like they are using a Mushroom as soon as they are snaking, so they will be able to go off-road without losing speed. As soon as the player does not have a turbo anymore from the start, the glitch ends. The glitch is very useful to do great Time Trial records.
Pipe Plaza Pipe Glitch
While going into a pipe at the same time as someone else, the player will end up far away from the area falling in the background.
Rainbow Road Double Glitch Shortcut
To perform these glitches, the player must choose Rainbow Road in Time Trial mode. First, the player has to start heading around the spiral road. When the player reaches the part of the spiral road that has the track heading towards the loop right above it, the player must turn around, sharply drift, and jump extremely close to the edge of the road in a corner that allows that player to get past the respawner and jump onto the section of the track right before the loop. Then the player should continue on until they reach another curve. That player should go through all five rings before the loop, turn around, and then shroom and jump off the edge to the left of the rainbow pipe that one could see by the curvy section of the track, while holding . If done correctly, the player should respawn by the corkscrew, and the lap shall count. 
Note: This shortcut is very difficult and sometimes when the player jumps correctly during the first part, that player may not get the lap count for unknown reasons.
Star Music Glitch
When the player quits or restarts any level or course, they will have a second of control before the screen fades to black. Usually, the music does not play while this happens. However, if the player during this short period picks up a dropped Star on the course or uses a Star, then the Star music will play, even though there should be no music. The Star music will cut out once the game is bought back to a menu, or the level has restarted.
Wario Stadium Wall Glitch
This glitch is very hard to perform and occurs rarely. On the first set of multiple bumps near the end, the player needs to boost over the bumps and head to the right (left in mirror mode). If done correctly, the player will fly on the top of the wall's corner and fall through it, before being picked up by Lakitu back to the normal track.
Wrong Starting Place
This glitch is only noticeable in Versus mode. If the player chooses Bowser Castle at first, the upper screen will show during the start of the race that the player's character is in 7th place, although clearly the character is behind the racer in 7th place. This glitch wasn't fixed in the Wii U Virtual Console release.
Yoshi Circuit Lap Skipping Glitch
Any character can be used to perform this glitch. On Yoshi Circuit, the player must go to the end of the first fence at the start of the course, then hit the end of the fence diagonally, and falling into the water. If the glitch has been performed correctly, then the character will be a few paces behind the finish line and when the player drives the wrong way around the track Lakitu should not be present, and the place counter should still be the same as when the player fell into the water. After the Yoshi nose section, the player can turn around and when they cross the finish line it will count as a lap.
Bowser Castle Moonjump
This is best done with Dry Bones with the Egg 1. The player should go to the left of the end of the spinning wheel and aim for the first dark-colored part of the spinning wheel. When the spinning wheel is rolling to the right, the player should use a mushroom and hop. If done correctly, the player will soar over the wall. If done at a certain angle, the player will land at the staircase at the beginning of the course.
Battle Opponent Freeze Glitch
In battle mode, if a CPU hits an item under a bridge in Block Fort, the CPU may get stuck under the bridge. Eventually, the CPU will sometimes recover unless the CPU is defeated.
CPUs Can't Use Items Glitch
If a CPU player is deploying an item, and a player or item hits their deployed item, then the CPU picks up an Item Box, the roulette will not stop fast, and if they get a deployable item, they will not do anything with it until they get hit by an item or obstacle. If they get an item like a Mushroom or triple shells, they will use the item, however. This is most noticeable in Battle mode with the CPU players set to hard.
Spiny Shell's Bad Day Glitch
In Waluigi Pinball, if someone uses a Spiny Shell in the area with the bumpers and pinballs, it may fly around the edges for a few seconds for unknown reasons before chasing after the leader.
Fall through the scenery
This glitch can be done in the Shine Runners mode. If the player wins while still under the effects of a Lightning, the character will fall through the scenery during the winning animation. Lakitu will pick up the character after falling.