Super Mario 3D Land ($39.96)
If you're a Mario player from way back, this will feel both familiar and new to you. It's a clever blend of 3D Mario design and perspective with 2D Mario-style stage layouts. It's also wonderful for bite-sized play sessions.
Mario Kart 7 ($39.99)
Everybody likes Mario Kart. You like Mario Kart. Even if you hate Mario Kart, you'll get hooked on it. This one has some nice online play, allowing you to lose to all your friends even when they aren't within taunting distance.
Cave Story 3D ($39.99)
This version of the classic Cave Story is ideal for people who don't identify as "retro" gamers, as it has fancy new graphics that disguise it as a new game. It's also great for people who want to see a familiar game in a new way. The important thing is that every single person should have a copy of Cave Story.
Bit Trip Saga ($39.95, currently eligible for buy one, get one half off)
Also in the "everyone should own" department: a collection of Gaijin Games' inventive, beautiful, rhythm explorations of the evolution of games. It's ... entirely likely you or your gift recipient failed to get these on WiiWare, so here they are in a nice portable format!
Super Street Fighter IV 3D Edition ($18.58)
If you're able to live without an arcade stick, you'll find a clever port of the industry-standard fighting game here, one that can be played with distant friends anywhere there's a wi-fi signal.
Dead or Alive Dimensions ($25.23)
The single-player mode is loaded with absolutely hilarious, freeze-frame cutscenes. Take that as a plus or minus according to your own preferences. But regardless of that presentation, the story mode in this game is the best fighting game training sequence ever designed.
Pilotwings Resort ($34.98)
A nice, mellow plane or jetpack ride around Nintendo's Wuhu Island is a good way to familiarize yourself with the 3DS. At least, it's mellow until you start getting into the later challenges.
Star Fox 64 3D ($37.99, currently eligible for buy one, get one half off)
Pixeljunk developer Q-Games updated the Nintendo 64 game with new graphics and new gyro controls. And, necessarily, the ability to put the whole thing in your pocket.
Nintendogs + Cats ($32.87 - $34.41)
Cute puppies and kind of cute, kind of uncanny-valley-ish kittens living inside your 3DS. If you're in the "people who like puppies" demographic, this is probably something you'll enjoy in short sessions. If you're not in that demographic, get the hell off of our website, creepo.
The Legend of Zelda: Ocarina of Time 3D bundle ($199.99)
Look at it! Look at it.
Power Pak+/Charge Base ($14.39/$19.00)
If you ever decide to use your 3DS as, like, a portable system ... out of your house ... you'll probably need one of these. If you have the extra scratch, it's nice to have the Charge Base for drop-in charging, but it's not necessary. (Update: Nyko reminded us that it also has the $29.99 Power Grip, which doesn't require unscrewing of the 3DS battery case, and has handgrips. Another option!)
Pro Pack Mini Plus ($29.96-$40.83)
If you want Skyward Sword, but don't plan to pick up the hardware bundle, why not get one of these smaller Wii Remote Plus controllers? It's a lot more comfortable for the epic journey between the A and +/- buttons.
Skylanders: Spyro's Adventure ($65.98 - infinity)
The Wii was the lead platform on this cute, collectible-laden game, so it's not a bad way to experience it at all. A bad way to experience it, we think, would be anywhere near a child, in a toy store. That would be a bad, expensive way to experience Skylanders.
Donkey Kong Country Returns ($43.99)
Yes, this is from last year, but you didn't buy it, did you? Even if you did, you know somebody who didn't. Buy it.
The Legend of Zelda: Skyward Sword ($49.99-$69.99)
What are you doing with a Nintendo system if you aren't even a little interested in Zelda? Or in motion controls? This is a Zelda game, with cool motion controls. And for twenty bucks more (if you can find it) you can get a fancy gold Wii Remote Plus to enhance the experience ... of looking at your hand while playing.
Rayman Origins ($45.98)
A delightful 2D platformer with co-op co-interference that will remind you of New Super Mario Bros. Wii. But with more slapping.
Kirby's Return to Dream Land ($49.99)
It's a simplistic platformer that keeps the player overpowered at all times, but it's also adorable, and perfect as an introduction to Kirby for kiddos.
Dragon Quest 6: Realms of Revelation ($24.80)
Take all the time you have for other games, and spend it recruiting monsters, leveling up in a variety of jobs, and traveling between a dream world and the "real" Zenithia.
Dragon Quest Monsters Joker 2 ($34.99)
Oh, your favorite part of DQ6 was the monster collecting? Well, how about a whole game about recruiting and training Slimes, Drackies, and other monsters from the RPG series? It's a Pokemon-type adventure in which you can capture, train, and even combine 300 monsters.
Ghost Trick: Phantom Detective ($14.11)
Combining unique puzzle mechanics and an unmatchedly odd story, Ghost Trick is an experience like no other. We can't seem to say anything about it that doesn't reference its singular nature. And sadly, given the sales, it'll likely remain singular.
Solatorobo: Red the Hunter ($33.30)
Developer CyberConnect2 indirectly recalls Mega Man Legends and directly recalls its own Tail Concerto with a classic action-RPG adventure. As adventurer Red Savarin, you go from floating island to floating island, taking on any quest you and your bipedal robot can complete.
Professor Layton and the Last Specter ($29.99)
It's a pretty safe bet as to whether you'll like this: if you a) liked any previous Layton game, or b) like puzzles even a little, you'll like Last Specter. As a nice bonus, once you've completed the atmospheric puzzle adventure (or while you're playing it), you have the London Life RPG to get lost in.
Aliens: Infestation ($29.99, currently eligible for buy one, get one half off)
Meet a bunch of newly invented Colonial Marines as you attempt (and mostly fail) to survive against xenomorphs, robots, and other threats aboard the Sulaco. It's equally great for Aliens fans and people who love a good Metroidvania.
Kirby Mass Attack ($29.99, currently eligible for buy one, get one half off)
This is the kind of bizarre experiment we've come to expect from Kirby -- a side-scrolling action RTS in which you control ten adorable puffballs at once.
Domo Starter Kit for DSi ($24.46)
Your DSi doesn't look like Domo-kun? What's that about?