See "Things to Do" and "Events" pages at link below for a list of things to do in the Stockyards. Do not skip the famous Cattle Drive, happening daily at 11:30am and 4pm. It's pretty amazing to see and provides some great photo opps.
Texas' largest honky tonk (think country music and line dancing)! This is a MUST DO and is conveniently located in the Stockyards.
There are some great breweries across Fort Worth and Dallas. Some recommendations are in the link below.
Stop by the historic downtown Main Street in Grapevine, TX. Here you will find lots of boutique shops, bars, restaurants, and most famously quite a few wine tasting rooms from wineries around Texas.
Mayfest is the biggest celebration of community in Fort Worth! Four days of live music, festival food, carnival rides, and performing arts.
Watch a Texas Rangers baseball game (in an air conditioned stadium) and stop next door at Texas Live! for some drinks and good food before or after the game.