While I was surfing the internet, I found that people from 75 and over use their free time mostly to watch tv, read and relax.
If this is your case, I will give you some other activities that you can do as a hobbie, because you still have a lot of time to travel and learn new things, and enjoy your free time, so why waste that time watching tv if you can do all those by yourself?

(Image credit: http://www.bls.gov/tus/charts/leisure.htm)

Here is a list of 10 things you might want to try while you still have time:

Start a newspaper 

Obtain a university degree

Learn how to read better

Run a marathon - Ed Benham was 84 when he ran a marathon in 4 hours, 17 minutes and 51 seconds

Help in volunteer organizations (if you are into that, here are some ideas http://www.howstuffworks.com/economics/volunteer/retired-volunteer-programs/10-best-volunteer-activities-in-retirement.htm#page=10), 

Keep working even when you retire 

Join an outdoor sports team (check the National Senior Games Association)

Travel 

Write a book

(Image Credit: http://www.personalbrandingblog.com/
personal-branding-interview-jane-buckingham/)

(image credit: http://blogs.windsorstar.com/2013/02/15/style-unleashed/)

Take home a pet who needs special care

By Margarita
http://www.elder-one-stop.com/retirement-ideas.html