This report from the National Association of Scholars quite effectively shows how a fine idea (common summer readings for undergraduates) has misfired in practice (by selecting ideological and trendy titles instead of more worthy books).
The last few pages of the report are what I am hoping you will look at -- the NAS provides a list of 37 books that they feel are actually "appropriate for any college common book program." I don't have a problem with any of the books on their list and I will confess that I haven't read them all but I am certainly looking forward to tackling Darwin's The Voyage of the Beagle and Dickens' American Notes for General Circulation, thanks to their recommendation. I would also like to obtain a decent copy of Stevenson's Eight Years of Trouble in Samoa.
As for beach reading for college undergraduates, two of the titles on the NAS list stand out, I heartily recommend both of them: Tom Wolfe's The Right Stuff, and Robert Penn Warren's All the King's Men. The former examines the heroic, and the latter, well, the true nature of politics.
And for when it's raining while you're at the beach, take the time and carefully read these other NAS recommendations: The Book of Job and The Book of Ecclesiastes (King James Version, of course). You will get tremendous bang for your buck (great wisdom per word ratio). After you finish the KJV, this translation of Job by Stephen Mitchell looks pretty interesting.