LOTS to do! There's Six Flags of course! Sea World (down the road from Six Flags), the Alamo, the Tower of the Americas (Near the Alamo & Riverwalk), the Riverwalk...has an awesome river tour ride, Chinese Sunken Gardens...totally free, just park & walk in & is adjacent to the San Antonio Zoo (there's a walkway from the gardens to the zoo so you don't have to get back to your car & repark, just walk on over if you want to goto the zoo!), I do have to tell you, the directions for the gardens seems incorrect online, I highly recommend following the signs to go to the zoo. You will see the gardens entrance first, then the zoo so if you act like you're going to the zoo, you will get to the gardens, otherwise you may get confused & lost...I definitly was confused by the way the sideroads were laid out in that area...with the directions, it just didn't match what the directions said so I thought I'd mention this to save some possible frustration you might have. The zoo also has the train ride outside the zoo entrance which also stops along the way so you can get out & see other things there before or even after your zoo visit, plus the burger joint there at the train is pretty reasonable on prices & is pretty good burgers but know they don't provide lids or straws for their cups! At least they didn't when we were there a few months ago. There's lots of restaurants like the Magic Time Machine off of Loop 410 that might be fun or you can eat at the riverwalk. Along the Riverwalk & Alamo, there's IMAX in the mall there at the Riverwalk as well as the boat ride which I highly recommend (extra fee for the ride but I think definitly worth it), along the Alamo area, walking distance, the tower of the Americas & across from the Alamo, there's Ripley's Believe it or Not museum & Guinness Book of World Records museum & various shops, there's Splashtown on I-35 downtown (in the same localized area) as well as Schlitterbahn up the road in New Braunfels (has free parking!!!) as well as Natural Bridge Caverns in New Braunfels that also has an adjacent Safari tour as well as the Snake Farm which has an animal park & petting zoo, also just off of I-35 in New Braunfels. If you don't mind a short drive north, just 10 miles north of New Braunfels, in San Marcos there is Aquarena Springs which is now owned by the college there & has been turned into a wildlife sanctuary but they have glass bottom boat rides, free admission to the park but the boat ride has small extra fee required but well worth it to visit! It has a nice history b/c it used to be a resort that offered a tower ride & sky ride, a diving pig and a mermaid show that you viewed from within a real sunken submarine & of course the glass bottom boat ride which they still have...definitly ride the boat and do the nature walk if you go. Also in San Marcos, there's WonderWorld, a cave system formed by a natural earthquake, they have a train ride and other activities there to do too plus the cave! (You take exit 202 off I-35N, turn left at the light, go all the way to the end of Wonderworld drive to the main intersection then turn right at the light & follow the signs but you have to pay attention to the sign where you turn left again in town otherwise you may miss it coz it kinda blends in. If you reach the square in town, you went too far...just an FYI b/c we liked to have never saw the sign...just thought I'd save you frustration, lol Plus just to clarify, you turn right onto Hunter Rd off of Wonderworld like you're going into town, don't cross over onto the new bypass otherwise you'll be going to Wimberley...Wonderworld, surprisingly, is actually in town). There's lots more to do in San Antonio but New Braunfels & San Marcos has things to offer too if you don't mind a short drive north on I-35. Corpus Christi is only a couple hours drive south if y'all wanted to visit the beach. I'm sure other posters here have more suggestions but as for me, the aforementioned is all I could think of on the spot, lol OH one more thing, if you take a short drive northwest past Six Flags on I-10, there's also Cascade Caverns in Boerne, Tx. Boerne is really not that far northwest, just looks like it on the map, neither is New Braunfels & San Marcos, just looks far on the map. If you're driving down to San Antonio on I-35 down from Dallas or Ft. Worth area, there's also Innerspace Caverns in Georgetown right off I-35 that you can visit on your way down, if not, just remember it's there in case you're ever in the area. There's also signs for it too in case you don't happen to remember. Hope this helps y'all w/your trip, there's SO much to do & if you can't do it all, that's ok, it'll leave some for next time! :) Have a great time & remember, you can normally print off discount coupons on most of the attraction websites! :)