I know summer is for sun, beaches and relaxing, but maybe it can be a good opporunity to grow in your understanding of God and His Word. There are so many good resources on the web to help with this. Here are two great resources that you can utilize:
1. Monergism Audio Resources - this site has links to all kinds of audio resources, including sermons, lectures, conferences, church classes. All of them are great (at least the ones I've listened to!).
2. Covenant Seminary Worldwide - this site is compliments of Covenant Seminary in St. Loius. It is the seminary of the Presbetyrian Church of America. The seminary is offereing a wide range of courses (usually consisting of twenty or more lectures) for free, though not for credit. Download and listen till your heart is content!