Eversave is a daily deal site similar to Groupon. I’ve purchased from them before and have not had any issues redeeming my voucher. One of today’s side deals is two tickets to the Houston Ghost Walk in downtown Houston. This walk is 90 minutes and says it is family friendly. I do not see an age limit, so you should call Discover Houston Tours to see what ages are allowed. Tours start September 30th and run on Friday, Saturday and Sunday evenings. (Don’t worry, this is not a paranormal tour.)
Also, the Groupon for the the 3 hour walking tour of downtown Houston is still available. Just remember that kids must be 6 or older.