If you can get together a regular group of people to attend, I can offer some tips to help convince merchants to give Bitcoin a try.
Set a regular schedule for your lunch mob so it is easy for members to set time aside and participate.
A few days before the lunch mob, visit the merchant and offer to "pre pay for a lunch party". Offer then $200 in cash to hold to get their attention long enough to tell them they need to spend a few minutes to learn about bitcoin wallets and how bitcoin works. Tell them your group wants to pay in bitcoin to them so they need to know how to use it. Then, after the lunch is over, you'll settle up with them on the bitcoin/cash - basically, you'll be buying the bitcoins back and they will want to keep the cash.
Sometimes they go for it. If they do, or if they don't, offer them a bitcoin tip jar for their register(s). Basically, a piece of paper that says "we are experimenting with bitcoins" and a verify url and tipping address for each register. If they are not interested in accepting bitcoins for meals, the tip jar is a solid fall back with zero risk to them as tips are never expected. Watch the address as your memeber so in to visit (encourage them to do so over the next couple weeks). When the tip jar gets $20 or so, pay them a visit again and show them the tips. Offer to buy those bitcoins for cash, but make sure you make them understand they have to do some work to get it like install a wallet, import the key, and spend it to you.