Celebrating Memorial Day is easy (kinda like the 4th of July), you just have to stick with the american colors... blow up blue/red/white balloons everywhere and decorate everything else with american flags!
Prepare what you like to drink and eat, and add a touch of "american colors" and here we go, you will feel like you are ready for a Memorial Day party!
Here are some recipes:
-Colorful cupcake: http://grinandbakeit.com/patriot-cupcakes
-All American strawberries: http://grinandbakeit.com/all-american-chocolate-covered-strawberries
-Watermelon stars: http://cleverhousewife.com/2012/05/watermelon-stars-perfect-for-4th-of-july/
-Flag cookies: http://www.tasteofhome.com/recipes/Sugar-Star---Flag-Cookies
Enjoy your holiday!