I also enjoy playing Sudoku on my Kindle Fire, but my favorite app on my phone is Moviepass. In combination with the card you can obtain from
www.moviepass.com, for $30 per month after a two-week free trial period, you can see movies at participating theaters for free. The only other rules are:
Only good for non-3D showings
No repeat viewings of the same movie
Only one movie every 24 hours can be seen
You must be within 100 yards of theater box office when selecting the movie
Participating theater chains include AMC, B&B, Screenland and Pharaoh. I've seen 9 movies in the past 15 days!