http://www.nintendo.com/eshop/offers/?gid=20140904SuperSmash
Looks like they're holding a four week sale on various 3DS and Wii U titles based on Super Smash Bros characters.
Week 1 9/4 - 9/11:
Super Mario Bros 3 (3DS/Wii U) - $3.49
Super Mario Bros 2 (3DS/Wii U) - $3.49
New Super Mario Bros U (Wii U) - $39.99
Super Mario 3D Land (3DS) - $19.99
Super Mario 3D World (Wii U) $39.99
Yoshi's New Island (3DS) - $29.99
Punch Out!! Featuring Mr. Dream (3DS/Wii U) - $3.49
Week 2 9/11 - 9/18:
Games based on The Legend of Zelda, Fire Emblem, Kid Icarus, F-Zero, Mega Man, and Sonic The Hedgehog
Week 3 9/18 - 9/25:
Games based on Pokemon, Metroid, Wii Fit, and Miis
Week 4 9/25 - 10/2:
Games based on Donkey Kong, Kirby, Pikmin, Star Fox, Pac-Man and Animal Crossing