The act of playing is the life line of our imagination. This we should be doing at any age. If all we do is work, then we miss the point of living.
Go to First Thursday on South Congress. I know it's a little crowded but it's still fun.
There's a free Movie at Union on Monday- it only happens once a month though. Alamo has it's two dollar Music Monday movie if your into music like I am.
Go swimming at Barton Springs or Big Stacy Pool. Nothing can tell you better that your living than swimming in cold water- Big Stacy is actually free, heated, and open all year round and Barton Springs is free after Halloween until Spring Break.