Free time is about relaxing your mind and refreshing yourself for more work ahead. So it shouldn't be used in worrying about how to plan some events or doing something that would add more stress to your life.
- Taking a vacation is good idea. Get away from all the work and relax for a while in an out of town location with family or friend(s) forgetting all the worries in your life.
- Get in touch with friends and relatives. Calling on people whom we've missed in a while and never really got the time to talk to in our usual days is a good thing too.
- Assess your life and what you've been doing. Thinking about where you're going and what needs to be achieved. Re-evaluate yourself.
- Get in touch with a hobby that's been neglected for a while. Re-discover your previous passions.
- Get a lot of sleep. If that's what you really want.
- Play an outdoor game like volleyball, football, basketball or cricket etc.