from one of my friends:
How old a guy are we talking about? Does he like to go out at night? Is he more fancy pants or hipster? I think either way the 'Blue Dome District' downtown (around 2nd and Elgin) is great. There are several places within walking distance around there worth checking out. There's the brand new Dustbowl Lanes and Lounge ('70s themed bowling and good food) right across from Joe Momma's Pizza (featured on Man vs. Food) and The Max Retropub (amazing '80s themed bar). There's also a McNellie's right around there as the ol' standby. There's a Mexican restaurant right around there too called El Guapo's (loose Three Amigos theme) with rooftop seating that affords a nice glimpse at the more admirable Deco elements of the downtown Tulsa skyline.
Brookside (between 31st and 41st and Peroria) is also a good area with lots of restaurants and some cool shops to check out during daylight hours. Philbrook is also right around there. I'm not sure what exhibit they'll be having in October, but regardless the permanent pieces and grounds in general are worth a look.
If he's more upscale he might enjoy Utica Square (21st and Utica). It's mostly an outdoor mall with upscale shopping but it has a few good restaurants. There's a Fleming's and a neat little place called The Wild Fork.
If he wants to see any of the more noteworthy architectural stuff (aside from the freakish straight out of Flash Gordon Oral Roberts University campus) there's also the Frank Lloyd Wright house, the attractively mid-century modern Lortondale houses, a deco tour of downtown (Mid-Continent Building especially), as well as some other gems here and there.
Just let me know what kind of stuff he might be interested in and I'll tailor the list a little more.