Mario Plushes: Walmart has a good variety of characters from the Mario Brothers games. I like how they have Koopa Troopa, Yoshi and Toad, not just Mario and Luigi. You can buy your favorite character or get the whole gang in a five pack.
Exclamation Mark Ring: I came across this website that sells handmade silver rings. To my delight, I found a Question Mark and Exclamation Mark ring. Both rings wrap around your finger but leave a space to truly represent the punctuation. They're subtle enough that they aren't geeky at all, but still have that old school videogame charm.
Portal Entrance Poster: Another piece that looks cool and subtle but means a lot to die-hard fans. These posters are made to order so you can request specific numbers for your Portal.
Legend of Zelda Ceramic Travel Mug: Be geeky and eco-friendly at the same time! This travel mug that says "It's Dangerous To Go Alone!" and "Take -> This," on the other side is awesome. I like the funny play on concept based on the videogame. It really could be dangerous to go to work without your usual cup of coffee or tea.
Pixel Bow: The last item in this roundup is specifically for the ladies. This cute pixel bow is another subtle reference to the inner gamer in you. It comes with a pinch clip whenever you need to make your ponytail a little cuter with a bow. (Images: 1. Julienne Lin; All others: As linked above)