Carley Jacobson over at the Instructables staff sent over her latest project we think is perfect for a slightly upscale summer picnic in the (Golden Gate) park: the Suitcase Picnic Table with Speaker System. It's a pretty simple project to copy, requiring only minimal materials and construction skills. You'll need a spare suitcase, the older the better, and a set of small USB powered speakers…
Sourcing a vintage suitcase might be as simple as snooping around your parents/grandparent's attic or basement (ask before, of course). We also recommend Goodwill, especially in neighborhoods with a high senior population, and checking out your local flea market.
Complete instructions about Carley's project over at Instructables/Suitcase Picnic Table and Speaker System.
If you're not in the DIY mood, you can always just order a similar styled suitcase-audio creation, sans table legs from an Illinois artist who specializes in the luggage meets audio equipment category: