There's a bar reminiscent of what you're thinking of in Oslo, Norway. It's very popular.
http://www.yelp.com/biz/tilt-oslo
A few tips which I believe have given them their success:
- Location. The bar is located in the middle of the main hipster/music scene nightlife area (as opposed to the upscale nightlife areas and the trashy nightlife areas). The city's most popular music venue is right next door, making it an ideal place to hang out before/after concerts.
- Shuffleboard. It's fun as fuck, rather cheap, it's played in groups of up to 4v4 rather than 1v1, it's very social and it's in the middle of the bar so everyone sees it and gets curious. This serves as a hook to get people to go there because it's something most places don't offer.
- Microbrews. A good selection of microbrews will attract a lot of people these days.
- Vintage arcade machines and pinball tables add to the atmosphere, but I rarely see people play them at night. Don't make this the focus of your bar.
- Moderation in terms of the "nerdy stuff" decor. No one is ashamed to go there due to the nerd stigma.
Basically, you need to appeal to a broad audience. Don't make it too nerdy, or you'll scare "regular people" away. you probably need to appeal to hipsters and other "alternative" crowds. Hipsters overlap with nerds, and generally go out more. You'll need these guys there to keep it running day in, day out.
As for the business aspects, listen to Eomer. Starting a bar is a really high risk project, most fail.