Apart from a new demo its a flash back update this week, you probably have played both these games before and one of them already might be on your Nintendo 3DS anyway.
3DS Virtual Console Punch-Out!! (NES, Nintendo, $7.50) The first non-ambassador NES title is on the eShop. But its up to you to decide if you want to pay for it again on the 3DS. It's quite good.
Super Mario Bros. (NES, Nintendo, $7.50) If you need me to explain what this is you need to be shot in the head. Now that's a bit harsh, but really I'll do it.
3DS Demos Mario and Sonic at the London 2012 Olympic Games (Sega, Free) The old 'Nintendo Fanboy' in me still is disgusted by this Sonic filth on my my Nintendo system. Not really but it's Sonic and Mario playing a whole bunch of Olympic games and it's quite good.