I used to go to the restaurant that had the bbq concession at Candlestick. They cooked their meat the old-fashioned way, over smokie mesquite. Melt-in-your-mouth meaty goodness.
I hope they have the concession at Levi.
Levi stadium reportedly has some very good grub ( bring tons of $$). Do go to Santa Maria for their local BBQ , too!!
http://www.sunset.com/travel/california/santa-maria-bbq -— and-—
http://www.seriouseats.com/2012/01/santa-maria-barbecue-california-tri-tip-sandwich-hitching-post-shaws.html