The rodeo is in town this weekend and next - that's fun and different for most people. The grounds have a life of their own apart from the actual rodeo - during the day it is family oriented and in the evening it gets to be more of a party atmosphere.
If you like to sidewalk shop, go to El Mercado and stroll through the Mexican shops there. It's interesting. Mi Tierra's and La Margarita are at El Mercado and have good Mexican food. You can take the trolley from your hotel to El Mercado.
As for eating on the riverwalk, I always go to
Casa Rio. It's the oldest riverfront restaurant and I like their food too. Original Mexican Restaurant is good too.