You could blog on your life, if its interesting and has new wild things happening often,
Your experiences.
Blog about something your an expert on, what you enjoy most, one of your most loved hobbies.
For example, celeb gossip > if you seem to know whats happening and celeb gossip interests you, you could expertise in that!
Fashion > if you know the latest trends, catwalk dates, clothing companies etc.
Some free sites:
Blogger
Wordpress
Xanga
Tumblr
Live Jounral
Mind say
New blog
20 six
Open Diary
^ Just a few
I hope this helped. Check out my blog for some inspiration.
Have a good day =)